AMGUEDDFAGENEDLAETHOL CYMRU NATIONAL MUSEUM OF WALES

WELSH FERNS A DESCRIPTIVE HANDBOOK

By H. A. HYDE and A. E. WADE

THIRD EDITION

CARDIFF PUBLISHED BY THE NATIONAL MUSEUM OF WALES 1954 REPRODUCED LITHOGRAPHICALLY IN GREA'l' DRITAIN Photo: D. G. H. Tttiton Frontispiece. COMl\ION FOLVPODV (Polypodium vulgare) GrOlving on the hunk of an oak tree PREFACE TO THE THIRD EDITION For this edition the authors have made only a few changes, prompted in the main by the writings of Professor Irene Manton, to whom their thaliks are due for permission to draw on her work. The greater part of the text has been lithographed from the Second Edition almost without alteration. In view of this, and to avoid unnecessary expense, capitals have been reta,ined for certain specific epithets, as the International Code allows. D. DILWYN JOHN, January 1954. Director.

PREFACE TO THE SECOND EDITION The text has been revised throughout 'for this edition, and . the opportunity has been taken to make v~rious minor alterations and improvements; no important change has been made, but a short section entitled' Hints to Collectors' has been added. D. DILWYN JOHN, ,October, 1948. Director.

PREFACE TO THE FIRST EDITION This the third of the series of Museum publications dealing with the botany of Wales has been written jointly by the Keeper of Botany and the Assistant in the Department. The former has written the Introduction and the various short notes on the interrelationships of the families and is responsible for the general plan of the work; the latter has compiled the notes relating to the distribution of the species in Wales and to 'first records'; and the descriptions which form the main feature of the work have been written jointly. The need for a simply written and inexpensive descriptive handbook to the Welsh Ferns is evident. Several such guides to British ferns in general were available to an earlier genera­ tion, and although these are all now in various ways out of date' in their outlook;s,everal of them are indispensable to the serious student; but nothing of the kind has been published for many years. Ferns, it is true, are treated, along with flowering plants, in the standard floras but only very briefly. In short, no comprehensive fern flora on the lines here attempted is now in print. The aim of the present work, therefore, is fIrst to enable the beginner, by means of the keys and the full descriptions which are given, and by tbe help also of the illustrations, to identify

hi 1V PREFACE all the' ferns he sees growing wild in Wales; second, to present the Welsh ferns in an evolutionary setting and thus to display the interrelationships of the various families and subfamilies, and finally to suggest the relationships of the Welsh fern flora to that of the world in general. It should be added that brief accounts of British ferns which do not occur in Wales have been inserted, though in smailer type: it is hoped, therefore, that possessors of Welsh Ferns will find that its usefulness is not confined to the Principality. In the pursuance of their aims the authors have laid many investigators under contribution. Their descriptions, though written entirely anew from the plants themselves, owe much to the older authors whose works are listed in the Bibliography on p. 125. The brief account of fern evolution and the notes on family relationships are all inspired by the writings of Professor F. O. Bower, and thanks are due to him for his generous permission to draw on his work and especially on The Ferns (Filicales). A scheme of classification founded on Bower's researches was drawn up tentatively and in outline, but.was abandoned on the appearance of Dr. Carl Christensen's Filicinae which, thanks to the kihd permission of its author, now forms the taxonomic basis of the main text. It should be added that Professor Bower's conclusions are here presented in very summary form and that the wording of Dr. Christensen's diagnoses has been modified in many places ·(though their substance· remains unaltered): the present· authors must therefore accept full responsibility for what they themselves have written. The authors' thanks are tendered to Mr. A. H. G. Alston, B.A., F.L.s., of the British Musenm (Natural History), for his valuable advice and assistance in regard to nomenclature. They wish also to thank Mr. D. G. H. Tutton for the photograph of Polypodi·um vulgare which forms the Frontispiece, and Dr. R. W. Butcher and Miss Strudwick for permission to use Figute 67. The ·line drawings, which form the great bulk of the text figures and most of which are designed to illustrate features emphasised in the text, have been made from nature by Miss E. A. Jenkins, B.Sc., working nnder the direction of the authors. Figures I to 3 and 5 to 9 are reproduced by arrangement with Messrs. Macmillan and Co., Ltd., Figures 4 and 11 by arrangement with the Cambridge University Press. CYRIL FOX, August, 1940. Director. CONTENTS Page LIST OF ILLUSTRATIONS ix INTRODUCTION: The life history of the male fern Homosporous and heterosporous ferns 9 The description of ferns 10 The stem or axis (p. 11) ';' hairs (p. 13), the leaf (p. 13) ; leaf-blade (p. 14). shape (p. 16). apex (p. 16). base (p 16). mr.rgin (p. 16), venation (p. 16); fertile leaves (p. 19), sorus (p. 20), indusium (p. 20), spomngium (p. 21) Classification of the ferns 21 Classification and evolution (p. 21), Bower's criteria (p. 22), Christcl1sen's scheme (p. 26) Geographical distribution of Welsh ferns. . 27 The British fern collection 1n the National Museum 30 Plan of the main text 31 Hints to collectors 32 Artificial key to the genera of Welsh fems 33

CONSPECTUS OF CLASSIFICATION. CLASS FILICINAE 37 Subclass 1. Filices Eusporangiatae 37 Order Ophioglossales 37 Family Ophioglossaceac 37 Genus 1. Botrychium Moonworis 38 Botrychium Lunaria Moonwori 38 Genus 2. Ophioglossum Adder's Tongues 40 1. Ophioglossum vulgatum Adder's Tongue 40 2. O. lusi"tanicum .. 42 Subclass 2.· Filices Leptosporangiatae 42 Order 1. Filicales 42 Family 1. Osmundaceae 42 Genus 3. Osmunda 43 Osmunda regalis Royal Fern 44 Family 2. Marsileaceae 45 Genus 4. Pilularia Pillworts 46 Pilularia globulifera Pillwori 46 Family 3. Hymenophyllaceae 48 Gemls 5. Hymenophyllum Filmy Ferns 49 1. Hymenophyllmll tunbrig­ ense Tunhridge Filmy Fern 50 2. H. peltatum Wilson's Filmy Fern 52 Genus 6. Trichomanes Bristle Ferns 53 Trichomanes spcciosum ]{illarney Fern 53

v vi CONTENTS Page Family 4, Polypodiaceae 54 Subfamily L Pteridoideae 55 Genus 7. pteridium 55 Pteridium aquilinum Bracken Fern 55 Subfamily 2. Gymnog'rammeoideae 57 Tribe 1. Cryptogrammeae 57 Genus S. Cryptogramme 57 Cryptogramme crispa Parsley Fern 58 Tribe 2. Gymnogrammeae Genus Ba. Anogramma 59 Anogramma leptophy Ha 59 Tribe 3. Adianteae 59 Genus 9. Adiantum Maidenhair Ferns 59 Adiantum Capillus-Veneris Maiden,hair Fern 60 Subfamily 3. ·Blechnoideae 61 Gt<;llUS 10. Blechnum 62 Blechnum Spicant Hard Fern 62 Subfamily 4. Asplenioideae 63 Tribe 1. Asplenieae 64 Genus 11. Phyllitis 64 Phyllitis Scolopendrium Hart's-tongue Fern 64 Genus 12. Asplenium .. Spleenworts 66 1. Asplenium rnarinum $,ea Spleenwort 67 2. A. Trichomancs lVlaidenhair Spleenwort 68 3. A. viride Green Spleenwort 69 4. A. obovatum Lanceolate Splcenwort 70 5, A, Adiantum-nigrum Black Spleenwort 72 6, A, Ruta-muraria Wall-rue 73 7, X A, Breynii A lternate leaved Spleen- 75 wort 8. A, septentrionale Forked Spleenwort 76 Genus 13. Ceterach 77 Ceterach officinarum Rusty-back Fern 78 Tribe 2. Athyrieac 79 Genus 14. Athyrium 79 1. Athyrium Filix-femina Lady Fern 80 2. A. alpestre 82 3. A, fiexile 82 CONTENTS vii Page Genus 15. Cystopteris Bladder Ferns " 82 1. Cystopteris fragilis Brittle Bladder Fern, . 82 2. C. regia 84 3. C. Dickieana 84 4. C, montana 84 Subfamily S. Woodsioideae 85 Genus 16. Woodsia 85 1. Woodsia ilvensis .. Oblong Woodsia 85 2. W. alpina ',' Alpine Woodsla 87 Subfamily 6. Dryopteridoideae 89 Tribe 1. Dryopterideae .. 90 Genus 17. Dryopteris Buckler Ferns 90 1. Dryopteris Filix-roas .Male Fern 91 2. D. abbreviata . Dwarf M ale Fern 92 3. D. Borred .. Golden-scaled Male 92 Fern 4. D. Villarsii .. Rigid Buckler Fern ,. 93 5. D. cristata .. Crested Buckler Fern" 94 6. D. dilatata .. Broad Buckler Fel'n " 94 7. D. ,spinulosa Narrow Bu'ckler Fern 97 8. D. aemula .. Hay-scented Huckler 99 Fern Genus 18 .. Polystichum Shield Ferns 100 1, Polystichum setiferum Soft Shield Fern 101 2. p, aculeatum Hard Shield Fern 103 3, P.- Lonchitis Holly Fern 105 Tribe 2. Thelypterideae 106 Genus 19. Thelypteris 107 1. Thelypteris palustris Marsh Fern 107 2. T. Oreopteris Mountain Fern 109 3. T. Phegopteris Beech Fern 111 Genus 20. Gymnocarpinm 113 1, Gymnocarpium Dryopteris Oak Fern 113 2. G. Robertianum Limestone Polypody 115 Subfamily 7. Polypodioideae 116 Genus 21. Polypodium 117 Polypodium vulgare .. Polypody Fern 117 Order 2. Salviniales 119 Family Azollaceae 119 Genus 22, Azolla 119 Azolla filiculoides Azolla 120 ApPENDl~ 122 LIST OF COLLECTORS 123 BIBLIOGRAPHY " 125 INDEX AND GLOSSARY 127 LIST OF ILLUSTRATIONS . ILLUSTRATIONS IN THE TEXT Page Fig. 1. r.Iale fern (Dryopteris Filix-mas) stock 2 2. J\'1ale fern: frond' .. 3 3, Male fern: sorus ,. 4 4. Male fern: sporangium 5 5. Male fern: germinating spores 6 6, l\'fale fern: prothallus 7 7. J\Iale fern: antheridia 7 8, Polypody (Polypodhmt vNlgare): arcbegonia .. 8 9, l\Iaidenhair fern (Adiantum Capillus- Veneris).; young sporophyte 8 10. Life history of a homosporous fern 9 11. Thin-walled and latticed scales .. 12 ~~; } Diagrams illustrating descriptive terms 15 14'. Some types of ve'nation 17 ", 15. Some types of indusium 20 16. Inter-relationships of families of ferns (diagram) 25 17. 1I1oonwort (Botrychium Lunaria) 39 IS. Adder's tongue (OPhioglossum vHIgatum) 41 19. Royal fern (Osmunda regalis): sporangia 43 20. Royal fern: pinnule 44 21. Pillwort (Pilularia globulifera): sporocarp 46 22. Pillwol·t: entire plant 47 23. Tunbridge. filmy fern (Hymenophyllum' tunbrigense) : sporangIa 49 24. Tunbridge :filmy fern: ripe sorus 49 25. Tunbridge filmy fern: portion of plant 51 26. Wilson's fllmy fern (H. peltatum): portion of plant 52 27. Killarney fern (Trichomanes speciosum): sorus 53 2H. Bracken f~rn (Pteridium aquilinum): sorus and indusia 56 29. Parsley fern (C1yptogramme crispa): sterile and fertile pinnae . . . . 58 30. Maidenhair fern (Adiantum Capillus-Veneris): pinnule 60 31, Hard fern (Blechnum Spicant): sterile and fertile segments .. 62 32. Hart's-tongue fern (Phyllitis Scolopendrium): portion of blade " .. 65 33. vVall-rue (Asple·1J.ium Ruta-mura,ria): sorus 66 34. Sea Spleenwort (A. marinum): pinna .. 67 35. Maidenhair Spleenwort (A. Trichomanes): pinna 68 36. Green Splecnwort (A. viride) pinna 69 37. Lanceolate Spleenwort (A, obovatum): pinna .. 70 38. Black Spleenwort (A, Adiantum-nigrum): pinna 72 39. Wall-rue (A. Ruta-mura'ria) frond 74 40. Alternate-leaved Spleenwort (A. Breynii): frond 75 41. Forked Spleepwort (A. septentrionale): frond .. 77 42. Rusty-back fern (Ceterach officinarum): portion of .frond 78 43. Lady fern (Athyrium F£lix-jemina) : pinnule .. 80 44. Brittle Bladder fern (Cystopteris Jragilis) : pinnule and sorus 83

ix x LIST OF ILLUSTRATIONS Page Fig. 45. Oblong Woodsia (Woodsia ilvensis) 86 46. Oblong Woodsia: pinna 87 47. Alpine Woodsia (Woods·ia alpina) 88 48. Alpine Woodsia: pinna ,. 89 49. Male fern (Dryopteris Filix~mas): sorus 90 50. l\hle fern: segment 91 51. Rigid Buckler fern (Dryopteris Villarsii) : pinnule 93 52. Broad Buckler fern (D. dilatata): pinnule 95 53. ·Narrow Bn,elder fern (D. spinulosa): pinnule .. 97 54. Hay-scented Buckler fern (D. aemula): pinnule 99 55. Soft Shield fern (Polystichum setiferum) : sorns 100 56. Soft Shield fern: pinnule .. 101 57. Hard Shield fern (P. aculeatwm): pinnule 103 58. Hollv fern (P. Lonchitis) : pil1i1a . . . . 105 59. Marsh fern (Thelypteris palustris) and segment 108 60. Mountain fern (T. Oreopteris) and segment 110 61. Beech fern (T. Phegopten's): third pinna 111 62. Beech fern: segment 112 63. Oak fern (Gymnocarpium Dryopteris): pinnule 114 64. Limestone Polypody (G. Robeytianum): pinnule 115 65. Common Polypody (Polypodium vulgare): segment 117 66. Welsh Polypody (P. vulgr1ye var. cambr'icum) 118 67. Azolla (Azolla filiculoides) 121

PLATES~ Common Polypody (Polypodium vulgare) Frontispiece Plate I. Royal fern (Osmunda rcgalis) Facing page 44 11. Killarney fern (TYichomanes speciosum), Parsley fern (Cryptogramme crispa) ai1d Maidenhair fern (Adiantum Capil­ lus-Veneris) 45 Ill. Hard fern (Blechnum Spicant) " 62 IV. Hart's-tongue fern (PhyUitis Scolopend­ rium) and Rusty-back fern (Ceterach officinarum) 63 V. Welsh Spleenworts (Asplenium viride, A. Trichomanes, A. Adiantum-nig­ rum, A. obovutum and A. marinitm) 66 VI. Brittle Bladder fern (Cystopteris fra{?ilis) , Lady fern (Athyrium Filix-femina) and Rigid Buckler fern (Dryopteris Villarsii) 67 VII. Narrow Buckler fern (Dryopteris spinu­ losa), Hayscented Buckler fern (D. aemula) and Broad Buckler fern (D. dilatata) .. 94 VIII. Hard Shield fern (Polystichum aculeatum) and Soft Shield fern (P. setiferum) .. 95 IX. Holly fern (Polystichum Lonchitis) 106 X. Limestone Polypody (Gymnocarpium Robertianum), Oak fern (G. Dryopteris) and Beech fern (Thelypteris Phegop­ teris) 107 INTRODUCTION The ferns or FILICINAE (Filicales) are regarded by botanists as a class of the PTERIDOPHYTA, * i.e. that division of the plant kingdom which includes not only the ferns (both recent and fossil) but also their allies, such as the horsetails and club­ mosses. The Pteridophyta in general were relatively far more important in the Palaeozoic Period than they are at present: the ferns proper were already represented, giant horsetails and clubmosses were abundant, and there existed in addition other classes of pteridophytes which have since become extinct. To-day the ferns proper far outnumber the remaining pteridophytes and, unlike most of their allies, they still hold their own in competition with the seed plants; moreover, their profusion and variety of form show that they are still in a state of active and vigorous evolution. The various classes of the Pteridophyta are grouped together on account of the basic similarity of their life-histories. In all of them the plant as ordinarily understood forms minute reproductive bodies called spores, each of which gives rise directly not to a new fern or fern-like plant but to a relatively simple and insignificant body called a prothaUus, from which the young fern plant later arises. Among the pteridophytes the ferns proper are distinguished by the fact that in them the leaves are always more strongly developed than the stem, often very large and much branched, and usually folded crozier-like in the bud. In most ferns the fertile leaves, i.e. those which bear spore capsules, are not otherwise distinguished from the sterile leaves and they are not confined to any particular part of the shoot; moreover, the spores. of ferns, unlike those of some of their allies, are liberated from the parent plant before they germinate. The relationship between the two alternating phases in the life-history of ferns in general may be exemplified by reference to the familiar Male Fern (Dryopteris Filix-mas (L.) Schott).

THE LIFE-HISTORY OF THE MALE FERN (Dryopteris Filix-mas) The plant (Fig. 1) consists essentially of a short stocky stem surmounted by a basket-like tuft of large leaves. The stock grows in length by the activity of an apical growing point; when very young the stock is small, but as it grows older it * Gk. 7rTEp{<; (pteris) fern; qWTfJV (phyton) plant. 2 INTRODUCTION wtdens out above so that its general shape becomes that of an inverted cone. The growing point is concealed by the young, as yet still enfolded leaves, and the rest of the stem by leaf bases spirally arranged on its surface. The stock branches

Fig. 1. Male Fern (Dryopteris Filix-mas). A, stock in longitudinal section: v, apex with growing point; st, stem; h, leaf stalks; bl, one of the still enfolded leaves; g, vascu­ lar strands. B j leaf. stalk bearing at k a bud with root (w) and several1eavcs. C, a similar leaf stalk cut longitudinally D, stock from which the mature leaves have been cut away to their bases leaving only those of the terminal. bud: W, w l , some of the numerous roots which fill the spaces between the leaves. E, stock from which the rind has been removed to show the network of vascular bundles (the plant's water- and food-supply system). F, a single mesh of the network enlarged, show~ng the smaller bundles which pass up into the leaf-bases. (After Sach!?) MALE FERN : LIFE HISTORY 3 but seldom. The thin wiry roots are borne at the bases of the leaf stalks. The fronds of the Male Fern (Fig. 2) are divided, after the manner of a feather, into pinnae and each pinna is similarly

Fig. 2. Male Fern (Dryopteris Filix-rnat). Fertile (Le. spore­ bearing) leaf about one-sixth natural size, the lower part with the unde!" surface exposed, To the left a single fertile segment bearing kidney-shaped sori, enlarged just over five diameters. (After Luerssen.) cut almost but not quite down to its main vein, or midrib, into a number of lobes or segments. If any frond taken from a vigorous plant be examined in the late summer it will be 4 INTRODUCTION found that, in the upper half of the frond at least, each segment carries on its lower surface a number of raised brown patenes called sari (sing. sarus) , which are arranged in two parallel rows one on either side of the midrib and nearer to it than to the edge or' margin of the frond. Each sorus stands above a veinlet which supplies it with nourishment.

Fig. 3. Single sarus of Male Fern (Dryopteris Filix-mas) in vertical section. The upper part of the section passes through a smal~ portion of the leaf blade and shows the upper and lower epidermis and in between them the assimilating tissue with H~ many air spaces. The sporangia are se'en attached by their stalks to the receptacle and (at this stage) protected by the indusium (which in section appears to be umbrella-shaped). (After Kny.)

The detailed construction of a sorus of Male Fern is illustra­ ted in Fig. 3. The essential structures are the stalked capsules called sporangia which 'spring from a swelling called the' receptacle and are, in the young stage at least, surmounted and protected by a kidney-shaped covering called the indusium. The head of each sporangium is shaped like a bi-convex lens; its margin is almost completely surrounded by a series of cells having thickened inner and radial walls, which together form a structure called the annulus; within are the dark-coloured MALE FERN: LIFE HISTORY 5 spores, 48 in number. The remaining thin-walled marginal cells stand on either side of a point (the stomium) at which the sporangium, when ripe, will open spontaneously, thereby liberating the spores. This process, called d,ehiscence, takes place- in dry air: the annulus cells, which contain water, dry up and the whole annulus shrinks and gradually bends back on itself (Fig. 4, A); finally the tension on the water in the annulus cells becomes too great, a gas bubble appears in each of them and the whole annulus recovers its shape with a sudden jerk, slinging the spores out into the air (B).* A

Fig. 4. Dehiscence and spore dispersal in Male Fern (Dryopteris Filix-mas). A, sporangium with the annulus bent back on itself. B, a similar sporangium after recovery by a sudden jerk. (After Bow'cr.) Each spore consists .of a single cell enclosed in a thin inner wall and a thick onter one. Given moisture and a 'suitable temperature it germinates. The outer wall bursts and the inner one protrudes, the one original cell dividing to form the prothallus which is at first thread-like, then later widens out until finally it becomes heart-shaped (Fig. 5). The fully formed prothallus (Fig. 6) consists of a single lay~r of cells, except below the notch of the heart where if swells out into a cushion several cells thick. The entire plantlet is attached to the soil and supplies itself with moisture and nutrient salts by means of hair-like root-cells called rhizoids. The remaining vegetative cells all contain chlorophyll, and the prothallus is therefore able under the influence of sunlight to assimilate carbon from the air and so to build np all the foods it requires: it is in fact, like the fern plant proper, a completely independ­ ent plant body. Unlike the fern plant, however, the pro­ thallus can live only under conditions of continuous moisture; moreover its reproductive processes, which are sexual in character, demand the presence of e,::ternal fluid water. * Ingold, C. T.: Spore Discharge in Land Plants. Oxford, 1939. 6 INTRODUCTION

The sexual organs consist of antheridia, or male organs, and archegonia, or female organs. Normally these are both borne on the lower surface of the same prothallus, the antheridia in the basal region or at the sides, the archegon~a on the cushion.

Fig. 5. Successive stages in germination of the spores of Male Fern (Dryopteris Filix-mas) to form the pr6thallus. (After Kny.)

The antheridium (Fig. 7) consists of a little knob projecting above the surface; when mature it contains a group of sperm cells which are liberated in the presence of external fluid water, each onc then slipping off its sheath to set free a freely mobile sperm. The sperm is essentially a small but highly organized speck of naked protoplasm; it consists of a spirally coiled body formed from the nucleus of the sperm cell and provided at its front end with a number of fine whip-like processes ~

~ f;; OJ M 7-1 Z

-i<') t-< ~ ~ ::q ~ [J) CS 7-1 ffii~~~i~~I'lzj ><: Fig. 7. Antheridia and sperms of Male Fern (Dryopteris Filix-mas). 4 and 5, develo- Fig. 6. Mature prothallus of Male Fern (Dryopteris Filix-mas) ping antheridia containing as seen from below, bearing antheridia among its sperm cells. 6, 7, ruptured antheridia and liberated -...] rhizoids and archegonia near to the apical notch. (Alter 8, Kny.)· sperms. single sperm high- ly magnified. (After Kny.) 8 INTRODUCTION called cilia; behind is a small spherical bladder which contains nourishment and is eventually discarded. The cilia lash themselves about and so propel the sperm through the water.

Fig. 8" Archegonia of Common Polypody (Polypodium f H vulgare). A, still closed: 0, egg (ovum); K , K , canal cells. B I a ruptured archegonium, with its neck open to receive sperms, (x 240.) (After Strasburger.)

The archegonium (Fig. 8) when mature comprises a large egg cell situated below the surface, together with a short tube of cells called the neel< which projects beyond the surface and which contains also two canal cells. The egg, like the sperm, is a speck of naked protoplasm; but unlike the sperm the egg is non­ mobile and passive and contains abun­ dant food material. In the presence of fluid water the cfmal cells tUrn into mucilage and. the neck bursts open. Sperms set free at the same time swim through the water, and are guided by chemical attraction toward the archego­ w' nium; one enters the canal and finally fuses with the egg. The fertilized egg Fig. 9. Maidenhair or zygote grows immediately into a Fern (Adiantum young fern plant, which though at first Capillus - Veneris). dependent for its nourishment on the Young plant at­ tached to· prothal­ prothallus soon becomes self-depen­ Ius, pp: b, first leaf dent and the prothallus rots away W, w', first and sec­ ond roots, It, rhiz­ (Fig. 9). aids of the prothal­ Ius. (About X 30.) The life history which has been (After Sachs.) briefly sketched above and which MAL~ FERN : LIFE HISTORY 9 applies to the ferns in general is summarized schematic ally below (Fig. 10). The fern life cycle is thus seen to be made up of two alter­ nating phases or generations (a) one beginning with the zygote and culminating in the formation of spores-this is called the sporophyte, (b) the other beginning with the spore

Fern plant ISp,mp;yt,) ~ Embryo ( . t Sporangium Zygote 1 ~ sp~o" SPt'm Et" Antheridium ,Archegonium

Pmth.lI" L_/ (Gamelophvle) Fig. 10. Diagram illustrating the life cycle of a typical hom.osporous fern. and culminating in the fusion of the two sexual cells or gametes: this phase is called the gametophyte. This handbook is concerned almost entirely with the sporophyte.

HOMOSPOROUS AND HETEROSPOROUS FERNS

The description of the life cycle of a fern given in the last preceding paragraph holds good for the great majority of families of ferns, in which the spores are all alike and in particular are all capable of giving rise to an independent prothaUus, which forms both kinds of sexual organs. There are, however, two families represented in Wales to which this does not apply without modification, viz. the Pillwort family (p. 45) and the AzoUa family (p. 119). These two families differ widely in many respects but they agree in forming two different kinds of spores (microspores and megaspores), and also (though quite incidentally) in being both composed of water ferns. A microspore is relatively small and on germina­ tion gives· rise to a male prothallus which is not capable of existing independently for any length of time, but which forms almost immediately a small number of male organs (anther­ idia). A megaspore on the other hand is relatively large; 10 INTRODUCTION it contains abundant nourishment and germinates giving rise to a prothallus which is able to live for some time at least an independent existence: this prothallus is purely female, and forms one or more archegonia. The embryonic fern plant which results from fertilization of one of the eggs is nourished at first at the expense of the food previously contained in the megaspore. The differences between the spores are reflected also in the numbers in which they are produced) the microspores being formed in large numbers in each microsporangium and the megaspores singly in each megasporangium. These differ­ ences are clearly related to what may be called a division of labour between the two kinds of spores: the function of the ·microspore is to produce many active sperms which shall seek out the eggs, that of the megaspore to produce a relatively small number of egg cells which shall passively await fertiliza­ tion and which, after fertilization, shall be able to give the embryo a good start in life. Fe,rns which form one kind of spore only are said to be homosporous; those which form two kinds are called heterosporous. . The condition of hcterospory has arisen many times in the course of evolution, not only in the ferns but also among other classes of pteridophytes... Moreover, various kinds of heterosporous ferns and fern-like plants have taken the further step of retaining the megaspore within the megasporangium, and have thus made the young embryo sporophyte directly dependent on the parent sporophyte. Such an em­ bryo, together with its wrappings, constitutes a seed. The several kinds of seed plants which exist or have existed, including the flowering plants proper and also the naked seeded plants (conifers, sago palms, etc.) of to-day, together with the Pteridosperms and other equally remarkable plants of past ages, all seem to have been derived thus from hetero­ sporous pteridophytes.

THE DESCRIPTION OF FERNS

One of the aims of this book is to enable its readers to identify all the species of ferns native to Wales. The ferns as a whole are perhaps the most easily recognized of all the great groups of plants: apart from such specialized groups as the filmy ferns and the water ferns there are very few ferns which cannot at sight be recognized as sllch. This uniformity in their general appearance makes the discrimination of one kind from another a much more difficult matter than with flowering plants. There are no short cuts to identification such as flqwers often provide. Attention must instead be focussed on features which at a summary glance the beginner would overlook completely : these features provide somewhat DESCRIPTION OF FERNS 11 subtle points of distinction, and ''if is- essential in a book like the present that they should be described in language which is both concise and exact. For this purpose it' is necessary to use a number of special words (such as glabrous, meaning devoid .of hairs) which are peculiar to botany, and to limit the use of certain other words to special meanings, as for example entire which, as applied to the margin of a leaflet, means 'devoid of any sort of toothing.' The majority of these technical terms aTe explained in the pages which follow, and they will all be found in the glossary at the end of the book. They have been kept as few as possible.

The Stem, or Axis One of the principal types of fern stem, viz. the stock, has been described on an earlier page under the head of the Male Fern: this type is found also in some other species of Dryop­ teris, and in Lady Fern (Athyrium Filix-femina), Hard Shield Fern (Polystichum aculeatum) and other ferns. The stock is short and thick and grow3 almost completely buried in the ground, and its growing point ascends at an angle to the horizontal; its leaves, apparently set in a circle or whorl around the growing point, actually are arranged in a very close spiral, and its roots spring from the backs of the leaf­ bases. The typical rhizome, on the other hand, is elongated and relatively narrow, it grows ,horizontal~y along, or beneath, the surface, and its leaves are borne on its upper surface singly at intervals usually in two rows (leaving the growing point naked except for hairs and scales), and its roots on its' lower surface; such sterns occur in Bracken (Pteridium aquilinum), Beech Fern (Thelypteris Phegopteris) and Common Polypody (Polypodium vulgare). There is no sharp line of distinction to be drawn between the two types: the stem in some ferns might with equal correctness be referred to either as .a,stock or as a rhizome. When the stern rises steeply, becomin&" almost erect, as in many of the stocky species, it is described as ascending. Other species, however, adopt a more or less horizontal, reclining attitude, with the growing point only ascending: the stem is then described as decumbent. Many ferns have stocky or ;rhizomatous' stems which, owing to branching, produce ,several heads of leaVes close together: such stems are called caespitose. A few ferns possess stems which differ from any of the above types. Thus in the Ophioglossaceae the stem is short and upright, producing (in the native species) only one leaf a year; and in Royal Fern (Osmunda regalis) there is a Inassive, branched, upright stock. . 12 INTRODUCTION

A B

Fig. 11. A, thin-walled scale of Brittle Bladder F:::rn (Cystopteris Jragilis); the terminal cell is glandular. B, latticed scale of Green Spleen­ wart (A splenium viride) , (About X 20), (After Sadebeck, from Engler and Prantl.) HAIRS AND SCALES 13

The surface of the stem at least when young, and commonly also later, is more or less thickly covered, with hairs or scales. Usually the hairs (e.g. in Bracken (Pteridium aquilinum) and the Filmy Ferns (Hymenophyllum) are coloured some shade of brown (from yellowish to almost black) and are jointed. The seales (Fig. 11) are coloured like the hairs, variously shaped (usually ovate to subulate) and more at less chaff-like; they are of two types (a) thin walled,' consisting of a single layer of cells with their walls of uniform thickness and (b) latticed,' consisting 'of cells having their abutting walls only strongly thickened and brown in colour, while the free walls are thin and colourless; scales of this type appear when magnified to be translucent with a lattice-like network of thick brownish black lines. Thin-walled scales occur, e.g. in the Bladder Ferns (Cystopteris) and the Buckler Ferns (Dryopteris); latticed scales characterize the Spleenworts (Asplenium), Rusty-back (Ceterach) and Hart's-tongue (Phyllitis) ; a latticed scale may have a two- or more-layered midrib which then, on account of the thiCkening and colouration of the inside cell-walls, appears as a dark line; e.g. Maidenhair Spleenwort (Asplenium Trichomanes). Both hairs and scales may be tipped with minute glands which exude some kind of secretion, e.g. Brittle Bladder Fern (Cystopteris jragilis) (Fig. 11, A).

The Leaf The leaves .(or fronds) of ferns in general. (Figs. 12 and 13) are strongly developed relative to the axis which bears them. They may be either spirally placed or set in two ranks. They are very rarely provided with the paired leafy outgrowths at the base of the stalk (called stipules) which are so common in flowering plants: among the types described in this book these structures are confined to Royal Fern (Osmunda regalis) and the family Ophioglossaceae (Moonwort and Adder's­ tongue). Except in the last named family apd in,the water­ fern Azolla the leaves of all Welsh ferns are enfolded crozier-like in the bud: i.e. their vernation is circinate. They are com­ monly, and especially when young, more or less thickly beset with hairs or chaffy scales similar to those of the rhizome but when mature may be entirely. without either (glabrous). Glands may occur either at the tips of hairs and scales (cf. Fig. 11, A) or as minute bodies closely attached to the surface of the leaf (e.g. Hay-scented Buckler Fern, Dryopteris aemula); glandu­ lar leaves are often fragrant and when fresh more or less sticky to the touch. In most ferns the leaf is constructed internally on lines similar to that of a flowering plant: the green assimi­ lating tissue is protected on the outside by an upper and a 14 INTRODUCTION

lower epidermis and permeated by a system of air spaces (cf. Fig. 3) which communicate with the outer atmosphere by means of adjustable pores called stomata; it is supplied with water and nutrients ,by means of veins. A leaf stalk (sometimes called the petiole) is usually present: in most ferns when the' leaf blade dies the hase of the stalk remains attached to the stem until it decays; in others however the stalk becomes detached either wholly, leaving behind a distinct scar on the stem (as in Common Polypody, Polypodium vulgare) or partly, the surviving portion remaining attached to the stem (as in Woodsia). . The leaf blade may be simple (undivided), as in Hart's­ tongue (Phyllitis Scolopendrium) , or it may be compound (divided), the characteristic form among ferns being that known as pinnate: in a leaf so organised a central' axis or rachis bears right and left of it numerous distinct leaflets called pinnae. The primary pinnae may again branch bearing pinnae of the second order, or pinnules: the leaf as a whole is then said to be bipinnate; the pinnules may again be divided up forming pinnules of the third order (pinnulets) , the whole leaf then becoming tripinnate.· A leaf or pinna may be built up on pinnate lines and yet not be divided into distinct leaflets: the name segment is given to any division into which a leaf is cleft whether completely to the midrib or not; when the segments are shallow they are called lobes and the leaf (or pinna, etc.) is said to be pinnately lobed; when the seg­ ments are at all deeply cut the leaf (or pinna, etc.) is called pinnatilid. In any leaf or part of 8 leaf the segments formed as the res'ult of the last degree of division are called the ultimate segments. In general the degree of division is greatest in the basal part of the leaf and decreases progressively toward the tip or apex not only of the leaf as a whole but also of that of each of the pinnae; the ultimate segments at the base of the lowest pinnae may be of the third order while toward the leaf apex they are of the .first. It is therefore convenient when describing a leaf completely to begin with the lowest pinnae and to work upwards. (It may here be. remarked that any general tendency, whether toward a smaller degree of division or in any other respect, is also traced from below upwards, and is often expressed by the use of the verb 'to become'; thus a leaf may be bipinnate at the base 'becoming' pinnatifid toward the apex, or a leaf stalk may be brown at the base 'becoming' straw coloured half way up, and so on.) When it is necessary to distinguish between the two sides of a pinna the one facing toward the apex of the frond is called the. LEAF BLADE 15

acros~opic side, ~he ot~er the bas£scopic side; in the same way all pmnules whIch pomt toward the leaf apex are acroscopic pinnules, while those which point the other way are basiscopic ; pml1ulets agam f!1ay be sin:.ilar1y distinguished in relation to the apex of the pInna of whIch they form part. The pinnae of

Fig. 12. Diagram of a compound frond to illustrate certain des­ criptive terms, A, B, opposite pinnae; C, DJ sub-opposite pin­ nae; A, stalked simple pinna with acroscopic basal1obe; B, stalked bipinnatc pi-nna (part of tripinnate frond); C, sessil~ simple pinna; DJ stalked pin­ nate pinna (part of bipinnate frond); E, simple pinna with Fig, 13, Diagram of a single aduate base; F, deeply pin­ pinna from a compound l1atifid pinna; G-P, segments frond, to show various kinds of the pillnatifid apical portion of margin: A, doubly ser­ of the frond; G, pinnately lobed rate; B, simply· serrate; .segment; H, oblong segment C, doubly crenate; D, with acute apex; j, oblong simply crenate; E, entire, segment with obtuse apex; K, The venation is Ctenop­ triangular segment with acu w teridian; at A the second­ minate apex; M, segment with ary vein is forked; at B spinulose-mucronate apex; N, the basiscopic tertiary vein segment with rounded apex; is forked and its acroscopic PQ, rachis; QR, stalk, branch is forked again, 16 INTRODUCTION a compound leaf may he either stalked or stalkless (sessile). They may stand opposite to one another or nearly so (sub­ opposite) or they may be alternate. The shape of the leaf blade as a whole, or of a single pinna or pinnule of a compound leaf may be described by the use of any of the following terms or comhinationsof them: Ovate: egg-shaped; obova!e: inversely egg-shaped; . lanceolate : tapering at both ends and somewhat broadened about one­ third from the base; triangular: broadest at the base and tapering therefrom to the apex; deltoid: shaped like an equi­ lateral triangle; linear,' narrow-several times longer than wide; oblong: much longer than broad, with parallel sides. FTequently the force of any of these terms is Cjualified by the use of an adverb sllch as 'broadly' or 'narrowly,' The apex of a leaf or pinna may be characterized according to its acuteness thus: acute: sharply pointed but not drawn out; acuminate.' drawn out into a point; mucronate: ending in a short straight point; spinulose,' ending in a small spine ;* obtuse," blunt or rounded; recurved,' curved outwards away from the main apex; incurved,' curved in towards the main apex. The base of a leaf or segment is thus described: cuneate: tapering; truncate: cut off at right angles to the midrib ; decurrent: running down the rachis (usually on one side only); unequal: asymmetrical. A segment is often so asymmetrical at the base that it is cuneate on one side and truncate on the other. A segment which is attached by the whole of its width td the rachis is said to be adnate thereto. The leaf margin may present a variety of shapes: entire: even, without toothing or division; serrate: toothed like a saw; crenate: scalloped; sinuate: waved; incised: deeply cut; crisped: curled; inflexed : bent inward and upward; reflexed: bent outward and downward. Throughout the ferns the shapes of the pinnae in one and the same plant vary very much according to their- position on the frond. The arrangement of the veins of a leaf is referred to as its venation. (The veins can often be seen more clearly if the leaf is held up to the light.) The primary or main vein of the leaf, or more usually of one of its segments, is called the midrib or, when less distinct, the mid-vein. Its branches are called secondary veins and their branches tertiaries. Veins of tertiary and subordinate grade are also called venules. The tertiary

* The spines of 'ferns hardly merit the name in comparison with those of some flowering plants, such as holly. VENATION 17 veins may be distinguished as acroscopic or basiscopic, accord­ ing as they come off the secondary on the side facing toward the apex of the segment or on the opposite side (cf. p. 15). The mode of veining of the pinnae varies very considerably from one kind of fern to another, but if attention is con­ fined to mature leaves the venation is found to be in some

Fig. 14. Types of venation. A, Coenopteridian (Hymenophyltum peltatum); ,B, Taeniopteridian (Phyllitis Scolopendrium).; C, Sphenopteridian (Asplenium Ruta-muraria); D, Pecopteridian (Atkyrium Filix-jemina); E, Neuropteridian (Osmunda regalis); F, Eupteridian (Polypodium vulgare) ; G, Cyclopteridian (Botrychium Lunaria). respects at least fairly constant within anyone species, and sometimes throughout anyone genus. This character has therefore been widely used for purposes of comparison and 18 INTRODUCTION

classification. A number of standard types of venation have been recognized; -some only of these are represented in the \Velsh fern flora and are summarized below for reference (cf. Fig. 14) :--

METTENlUS' TYPES OF VENATION (as represented by Welsh ferns)

1. Coenopte~Js type:* each- undivided leaf, or segment of a divided leaf, has one unbranched midrib, e,g. Wilson's Filmy Fern (Hymenophyttum peltatum) (Fig. 14, A). 2. Ctenopteris type: a series of simple or forked secondary veins arise in pinnate order from the primary vein; the three following types (3-5) may be distinguishec. according to the angle which the secondaries make with the midrib. 3. Taeniopteris type: the secondary veins leave the midrib approxi~ mately at right angles and run straight to the margin, while any tertjary nerves which occur run parallel with the secondaries, e.g. Hart's-tonglIe (Phyllitis Scolopendr-ium) (Fig. 14, B). The short basal curves usually present in ~he secondarfes in this type are ignored. 4. Sphenopteris type: the secondary veins leave the midrib at an acute angle and pass, together with the acutely angled tertiaries which spring from them, straight to the margin, e.g. Wall-rue (Asplenium Ruta-rnuraria) -(Fig. 14, q, and other Spleenworts. 5. Eupteris type: the angle made by the secondaries with the midrib is midway between the extremes of 3 and 4, e.g. Common Polypody (Polypodium vulgare) (Fig. 14, F). 6. Neuropteris type: the secondaries issue from the midrib at an acute angle (as in type 4), then turn toward the margin curving convexly in relation to the midrib and, together with their branches behave, as to the outer half of their course, like the secondaries in type 3, e.g. Royal Fern (Osmund(), regalis) (Fig. 14, E). 7. Pecopteris type: tertiary veins issue in a pinnate arrangement from the secondaries, remaining undivided or less often becoming once more pinnatcly divided, e.g. Lady Fern (Athyrium Filix­ jemina) (Fig. 14, D), Woodsia and various species of Dryopteris. 8. Cyclopteris type: the midrib disappears completely at the base of the leaf blade (or of the leaf segment as the case may be) giving rise by repeated dichotomy to a fan-like system of subordinate veins, e.g. IVIoonwort (B,otrychium Lunaria) (Fig. 14, B), Maidenhair Fern (Adiantum Capillus-Veneris). In all the above types the vein-endings are free and the venation is described as open. This applies to all Welsh ferns, with very few exceptions, the most obvious being Adder's­ tongue (Ophioglossum vUlgatum) and Rusty-back (Ceterach) , in which cer.tain or all of the veins fuse. together or anastomose to form, in the one, a completely closed network and, in the other, a series of loops. To these must be added Pteridium

* This and types 2 and 5 are named after genera of living ferns, the remainder after fossil genera either of ferns or of fern-like seed plants (Pteridosperms). VENATION 19 in which the otherwise free ends of the veins are linked together by a commissure formed by vessels which run along the margins of the leaves beneath the sari (cf. p. 55), and also Blechnum in the fertile leaves of which the secondary veins form an obvious commissure running parallel with the -margin (p.62). Although the venation in ferns may be regarded, as in the series of types summarized above, as being made up of primary veins giving off secondaries, secondaries giving off tertiaries and so on, in actual fact the ultimate veins at least almost always branch by equal forking (true dichotomy). This is seen for example in Hymenophyllum peltatum (Fig, 26) where the veins supplying the ultimate segments spring from the main vein which runs the whole length of a pinna. This main vein may be regarded equally well, however, as being built up of short pieces each' resulting from an unequal forking, the stronger branch of each fork appearing as a portion of the main vein while the weaker appears as a branch going to an ultimate segment. Similarly the midrib of the entire frond may again be regarded as having been built up by successive unequal, dichotomies. In other ferns there is a more clear-cut dis­ tinction between axial vehls and 'lateral veins, but all appear to have been derived in the first place from a system of dichotomous branches. Fertile Leaves As already stated the fertile or spore-bearing leaves (sporo­ phylls) of ferns are· in general hardly distinguishable from sterile or non-spore-bearing leaves. Among Welsh ferns the ,exceptions to this statement are: Hard Fern (Blechnum Spicant) and Parsley .Fern (Cryptogl'amme crispa), ill which the fertile leaves are longer and have narrower pinnae and together form a distinct whorl; Royal Fern (Osmunda regalis) , in which the upper pinnae only of the fertile leaves bear spores; and the two ferns belonging to the Adder's-tangue family, in which the leaves are divided into a hinder sterile blade and a nearer fertile spike. The most usual position of the sporangia is on the under surface of the leaf and away from the margin as in Male Fern (Dryoptel'is Filix-mas) , but they may be located near the margin as in Bracken (Pteridium aqu£linum) and Maidenhair Fern (Adiantum Capillus-Veneris) or actually on the mar:gin as in the Filmy Ferns. As a rule the sporangia arise only above the veins and usually on a more or less strongly marked swelling called the receptacle, and form distinctly circumscribed groups known as sari; in Royal Fern (Osl11Unda regalis) however the sporangia are not grouped into definite 20 INTRODUCTION sori, while in Moonwort (Botrychium Lunaria) they are borne singly. The sorus may be entirely nai

Fig. 15. Some types of sorus and indusium. A, marginal sarus with two~1ipped indusium (HymenophyUum tunbrigense). All ,the remaining examples are superficial. B J circular sarus with basal indusium (Cystopteris jragiUs),_' C, circular sarus with kidney­ shaped indusium attached at the notch (Dryopteris Filix-mas), DJ circular sarus with peltate indusium (Polystichum setiferum), E, linear sarus and indusium (Asplenium Trichomanes) , F, paired linear sori with indusia facing and overlapping (Phyllitis Scolo­ pendrium). (Aspleni·um) (Fig. 15, E) the indusium is linear in shape and extends along a fertile vein; in the Filmy Ferns (Fig. 15, A)· it encloses the base of the receptacle, forming a sort of bivalved cup; in Bladder Ferns (Cystopteris) (Fig. 15, B) and Woodsia it is placed at the base of the sorus which it more or less covers from below; in the Bnckler Ferns (Dryopteris) (Fig. 15, C) it INDUSIUM 21 surmounts the entire sorus as a kidney-shaped (reni/orm) shield and in the Shield Ferns (Polystich1

(~) CRITERIA RELATING TO VEGETATIVE CHARACTERS 1. The external morphology of the shoot. The upright habit of growth as seen in Osmunda is held to be primitive and the prone' position, seen for example in Common Polypody (Polypodium vulgare) , to be derived. The primitive method of branching of the stem is by forking (dichotomy) ; the two limbs of the fork may remain of equal importance or one may grow more strongly than the othel:. 2. The segmentahon of the cell or cells forming the apical cone or growing j)oint of the stem, leaf and root. In the Lcptosporangiate ferns (cf. p. 42) a single initial cell is present at the apex of stem, leaf and root, and its divisions follow a strict and simple rule. In the Eusporangiatae, on the other hand, well~grown stems, leaves, and roots grow by means of a group of cells, not a single celi, and their divisions are neither simple nor regular. Viewed thus, the Ophioglossaceae and Osmundaceae occupy an intermediate posi­ tion. The fiI;st-named group is the most advanced and specialized in respect of this as of other characters. 3. The architecture and venalion of the leaf. The leaves of ferns are remarkable in that they ccntinue to grow at the apex for a consider~ able time after they are first formed. In all species the ultimate segments (which are also the last to be formed) show dichotomous veining, which is an ancestral character. The earliest ferns are suppooed to have possessed dichotomously branched leaves with a single vein to each lobe (as in Hymenophytlum, cf. p. 18). Lobes BOWER'S CRITERIA 23

and segments with more complicated venation have arisen in the course of evolution as the result of lateral fusion ('webbing') between the primitive single-veined lobes, 4, The vascular system of the stem and leaf. If the veins are traced dow-n into the rachis they arc seen to join up, forming thicker and thIcker vascular bundles which pass down through the leaf-stalk into the stem, where they become merged in the stele-the collective name for the system of channels for the movement of water and nutrients throughout the stem and roots. In the simplest and earliest ferns the stele was a cylinder of simple construction, and resembled a thick vein running down through the middle of the stem; while in later and especially in larger types the stele becomes more and more complicated (cf. Fig. 1, E) ; but further consideration of the subject is outside the scope of this book. 5. The dermal appendages. Hairs and scales arc found in all families of ferns, includi,ng even the Ophioglossaceae and the water ferns, both of which possess such appcndages in their younger stages. Simple hairs are a primitive feature; branched hairs and in particu· lar flattened scales are more advanced ones.

(E) FEATURES RELATING TO REPRODUOTIVE CHARACTERS

6. The sor'US: its structure, position and relations. (a) Structure: There are three main types of sorus, referred to as simple, gradate and mixed respectively. The simple sarus is set on a low receptacle and contains a small number of sporangia, all of which ripen and shed their spore.'3 simultaneously. No fern having a typically simple sorus is native to Europe; cultivated examples of sl1ch, e.g. species of Gleichenia may, however, be seen in this country among collec· tions of ferns grown under glass. In the gradate sorus the recep· tacle stands up from the surface of the leaf and the sporangia are formed on it successively, the oldest at the top and younger ones lower down. The best examples of gradate sari are contained in the Hymenophyllaceae: thus the bristle of the Bristle Ferns (Trichomanes) is the elongated receptacle. The gradate sorus has the advantage over the simple sorus that spore prdduction is spread over a longer time and therefore involves less strain on the plant's organs of nutrition, while at the saOle time the spores have a better chance of dissemination. In the mixed sorns spo~angia of different ages are aggregated together without any definite sequence. Younger sporangia arise promiscuously between those already formed. The great majority of ferns have mixed sari. In the earliest ferns the sporangia were solitary; then came ferns with simple sari (Simplices); later gradate sari evolved among various groups of ferns (Gradatae); and finally ferns with mixed sari (Mixtae) arose either directly from forms having a simple sorus or indirectly through gradate types. The three groups thus repre­ sent levels in evolution, and the Mixtae of to-day represent the results of parallel development along several lines. (b) Position and relations: In most ferns the sari are borne superficially, i.e. on the lower surface of the leaf: each is seated upon a vein, frequently on a nerve ending. In some, e.g. the Filmy Ferns, however, the sari are on or near the margin of the leaf. Comparison between certain ferns which in almost all respects are so similar that they must be closely related shows that they may be arranged in series in which a species with marginal sari is at one ( 24 INTRODUCTION

end of the series and a species or more than one with superficial sari at the other. Such series exemplify a process which has often bappened in the course of fern evolution. In the ancestral ferns the sori were always borne on the leaf margins; when the leaves increased their surface area (by 'webbing') the sori, instead of being carried out with the margin, stood,still and so came to occupy a position on the under surface. Such a development may actually be traced in the individual life history of certain ferns: the sari originate on the margin only to be deflected to the under surface by the later growth of the leaf. Those families ot ferns (such as HyroenophyUaceae) which have retained the marginal type of smus, have been grouped together by Bower as Marginales " others, in which the sarus has long ago 'slid' to the lower surface, are called by him Supt;rficiales. 7. The protection of the sorus. The young sporangia require protection, which they get in the first place from the coiled-up leaf and from the hairs and scales. In the earliest ferns no other protection was present but later special organs of protection arose: these are described in general as indusia (cf. p. 20). Among the Marginales, e.g. in the Filmy Ferns, the indusium takes the form of a more or less two-lipped cup. l\Iarginal rows of sori so protected are sup­ posed to have become fused to give the coenosori, fringed with upper and lower indusia, seen in the Bracken Fern. A one-sided basal type of indusium is seen ,il certain ferns having superficial sori : this type, seen in Woodsia and Dryopteris, is distinct in origin from the indusium of the 'marginal' ferns. 8. The characters of the sporangium. The great majority of living ferns possess sporangia similar to those of the Male Fern (p. 4) : typically each consists of a narroW stalk surmounted by a capsule containing a relatively small number of spores (usually sixty·four, forty-eight or thirty-two) which are liberated by the action of a specialized vertical roW of cells called the annulus. The entire sporangium is formed from a single cell which undergoes repeated divisions: it is called a leptosporangium. Study of fossil shows that the earliest ferns possessed more massive sporangia which were either sessile or attached to a rela­ tively short thick stalk, and which contained large numbers of spores (1,000 or more). They had no annulus. Sporangia of this type are found to-day among the Ophioglossaceae. Each arises not from a single cell but from a group of cells and is called a eusporangi1tm. The major division of the Filicinae into Filices Eusporangiatae and Filices Leptosporangiatae corresponds in the main to the above distinctions, except that the Osmundaceae, which are known to be an ancient family and which possess sporangia intermediate in type between the two kinds described, are nevertheless grouped with the Leptosporangiatae. '9. The prothallus. The gametophyte generation of ferns lies outside the scope of this book. It must suffice to say that in general comparisons between the prothalli of different families of ferns reinforce the conclusions (as to their relative antiquity and relation­ ships) which have been drawn from comparisons between the fero 'plants' proper. Bower's application of the criteria summarized above led him to put forward a scheme which in his view represented EVOLUTION OF FEIl."S 25 the general course of evolution among the ferns. On this view all the various families can be traced back to a comma n origin in the extinct Palaeozoic family Coenopteridaceae, * so named because its members had various characters in com­ mon with different families of modern ferns .

.J ~ ~ JI1IXTAE

Fig. 16, Diagram showing the inter-relationships of the families of British ferns and some of their subfamilies. The names of certain foreign families which provide evolutionary links have also been inserted. All are regarded as having been descended from the Palacozoic family Coenopteridaceae. (After Bower, modified.)

The families of ferns at present extant were grouped by Bower in the first place (as already stated, cf. p. 24) according to the prevailing position of the sorus: in his MARGIN ALES the sori are situated along the margin of the frond or segment,

* Gr. Koty6~ (coinos) common, cf. Seward, Fossil Plants, Val. 11, p.433. 26 INTRODUCTION

while in the SUPERFICIALES* the sari are situated on its lower surface. The British families included in the Marginales are Ophioglossaceae and Hymenophyllaceae. together with the subfamily Pteridoideae. The Superficiales include the greater part of the Polypodiaceae, viz. the subfamilies Woodsioideae, Dryopteridoideae, Asplenioideae and Blechnoideae. The Osmundaceae and also the subfamily Gymnogrammoideae are rega4Cied as occilpying a position between the 'marginal' and the 'superficial' ferns: their sori are ill-defined at best and they have no indusium properly so callei!. Within each of the three groups, Marginales, Superficiales, and 'intermediates,' a progression has taken place from .primitive types (such as Ophioglossaceae and Osmundaceae) having a simple sorus ('Simplices'), to more advanced types (such as Hymenophyllaceae) having a gradate sorus ('Grada­ tae'), which lead on in their tnnl to the most highly evolved ferns (forming the great majority of living species) in which the sorus is mixed ('Mixtae'). These relationships are .illus­ trated in the diagram (Fig. 16). The British fern flora does not possess representatives of sufficient families to illu~trate evolutionary relationships at all clearly, and the names of certain foreign familiest have therefore been introduced as connecting links. It is not suggested that anyone existing family has necessarily given rise to another higher in the evolutionary scale but only that, to take one line of progression as an example, ferns related to the Gleicheniaceae gave rise to ferns related to the Cyatheaceae, from which the Dryopteroid ferns in their turn were derived. In addition to soral characters Bower employed all the other criteria above referred to, in an endeavour to assess the relative primitiveness or otherwise of the various· groups. He did not, however, propose a detailed classifi­ cation of the entire fern phylum: this has been undertaken more recently by Christensen, whose system is based on the results of modern research and also, as he himself adds, on an intimate knowledge of four-fifths of all known ferns. It is not final because our knowledge of the anatomy and morphology of many ferns is incomplete, but it does attempt to indicate, as far as is possible in a tabular arrange­ ment, the evolutionary relationships between the various groups and it has therefore been taken as the basis for the

>I< These names, like Simplices, Mixtae and Gradatae, are descriptive rather than strictly taxonomic and do not appear in the system of classification set out later. t See Appendix. GEOGRAPHICAL DISTRIBUTION 27 present handbook. A conspectus of Welsh Ferns arranged according to Christensen's scheme is set Qut in the contents pages. THE GEOGRAPHICAL DISTRIBUTION OF WELSH FERNS Of the 6,000 or so known species of ferns only forty-two (0'7 per Gent) inhahit \Vales, but these comprise representatives of twenty (13 per cent) out of the 150 known genera and six (37 per cent) out of a total of sixteen families. Fifteen of the genera which occur in Wales contribute only one species each to the Welsh list, although with one exception they each contain other (i.e. non-Welsh) species. The Welsh fern flora is.in ,fact much more widely represf;:ntative of the class Fili­ dnae than its small size would lead .one to expect, and it becomes of interest to discover what are its geographical relationships to the fern flora of the world as a whole. The distribution of ferns in general is strictly limited by climatic conditions: they demand a damp and at least moderately warm climate. Moreover the majority aTe shade plants: their world area of distribution therefore falls almost though not entirely within that of forests and woodlands. These facts may be illustrated by estimates of the comparative importance of ferns in the total floras of various countries: for Wales 3·6 per cent, for the British Isles as a whole 2·85 per cent, for France 1·73 per cent, for Greece 1·2 per cent. The great majority of ferns are tropical. Out of 150 genera only thirty-three are not represented in the tropical forests. Twenty-three genera are found in the temperate woodlands of the northern hemisphere: only seven of these do not occur in the tropical forest region. The larger types (including the tree ferns) are all confined to the warmer regions of the world. H. Christ of Basel has given the completest account of the geography of ferns yet published. He grouped all the known species of ferns nnder a number of types of distribution, which may be snmmarized and illustrated by reference to the Welsh flora thus :- 1. The Cosmopolitan element: composed of species which occur in the Old and New Worlds and in the Northern and ~outhern Hemispheres, and occupy a considerable: area also in the Tropics. 'Nine species in Wales (out of twelve in the world flora), viz. Osmunda regalis Asplenium Trichomanes I-Iymenophyllum tunbrigensc* Athyrium Filix-femina " peltatum* Cystopteris fragilis Adiantum Capillus-Vencris* TheJypteris palustris Pteridium aquilinum * In Europe belong to the Mediterranean region: see p. 29. 28 INTRODUCTION

2. The Pantropical element: ranging more or less through the Tropics. Out of about 120 species only one in Wales, viz. Trichomanes speciosum 3. The Circumpolar element: occurring throughout the north temperate zone only. Approximately forty-six, or one-fifth of the total fern flora (200) of the north temperate forest region; in Wales fourt~en species, viz. Ophioglossum vulgatum Dryopteris dilatata Blechnurn Spicant Thelypteris Oreopteris Phyllitis Scolopendrium " Phegopteris Asplenium viridc Polystichum Lonchitis Rutft-muraria Gymnocarpium Dryopteris " septentrionaie " F.obertianum Dryopteris spinulosa POIypOlJium vulgare 4. The Arctic-alpine element: occurring far to the north and otherwise confined to high mountains though over a wide area. A very small element, including in Wales only Cryptogramme crispa VV. alpina Woodsia ilvensis (Cystopteris jragilis and Dryopteris spinulosa are sub-arctic; Polystichum Lonchitis is alpine.) 5. Bipolar species: occurring widely in the Northern Hemisphere anc! also in the Southern, but not in the Tropics. One only: Botrychium Lunaria The remaining species have a more restricted or a doubtful distribution. The worlel range of \Velsh ferns may therefore be summarized thus:- Cosmopolitan 9 Pan tropical 1 Circumpolar 14 Arctic-alpine 3 Bipolar .. ., 1 Restricted or doubtful 14 42 The temperate ferns may be only a small minority but, as this analysis of the Welsh fern flora shows, many of them range very widely over the world. Dr. Christ divides the world into t.welve regions, each of which has its characteristic fern flora: Wales stands on the extreme edge of one of these, viz. the cool-temperate northern woodland region, where this region merges into that of the Mediterranean and Atlantic seaboard. The majority of Welsh ferns belong to the cool-temperate woodland flora: all GEOGRAPHICAL DISTRIBUTION 29 species listed under types 3, 4 and 5 belong here, together with most but not all the cosmopolitan species referred to on p. 27. Welsh species belonging to the Atlantic flora include Hymenophyllum tunbrigense Asplenium obovatum "peltatum "marinum Trichomanes speciosum Dryopteris acmula

The following are morc Mediterranean:- Adiantum Capillus-Veneris Dryoptcris BOlTed Ceterach officinarum Poly~tichum setiierum

In referring to the presence of the I\Ieclitcrranean group in Ireland, Dr. Christ makes the comment that that country has a·fern flora which by reason of its southern character in so high a northern latitude is unique. \Vales is a much smaller country than Ireland and- it extends no farther south: yet it probably possesses the same range of southern forms (with the single exception of Asplenz'1l11t Adiantum-111'gr1l1J1, var. Onoptcn:s) and is the home r.noreover of several other species which are not found in Ireland. To the plant geographer thcrcforethe Welsh fern flora owes its chief interest to the position of \Vales on the Atlantic seaboard of Europe (and thus under the influence of the Gulf Stream) and the consequent mingling of species characteristic of two different floral regions .. The effect of this favoured situation may be brought out further by con­ trasting the fern flora of Wales on the one hand and that of East Anglia, the driest part of Great Britain, on the other. Caernarvonshire possesses forty species of ferns, Merioneth thirty-six and Glamorgan thirty-three, while Cambridgeshire has only thirteen now known to be extant and probably none of the' vice-counties '* into which Norfolk and ,Suffolk have been divided has more than twenty, if so many. If the numbers of individual plants are considered the differ­ ence is even more marked. Apart from BraCKen (Pteridium aquilinum), probably the only fern which is an important element of the vegetation anywhere in East Anglia (and that only very locally) is Marsh Fern (Thelypteris palustris). In Wales by contrast several woodland species such as Male Fern (Dryopteris Filix-mas), Broad Buckler Fern (D; dilatata) , and Hard Shield Fern (Polystich-um aeuleatum) often occur in abundance, while Hart's-tongue (which in East Anglia and in parts of the English Midlands is confined to wells and such places) is known completely to cover the floor of some lime­ stone woods in South Wales .

... See footnote p. 30, 30 INTRODUCTION

In the main text the distribution of each species is dealt with in three short paragraphs. The first contains a state­ ment (in terms of 'county records't) of the plant's occurrence in Wales: this information has been compiled as the result of a systematic search through most if not all the books and papers relating to the subject which have been published since the year 1597 (the earliest records so discovered are also stated, but in another paragraph). The second paragraph summarizes more briefly the plant's distribution within the British Isles and the third states its world distribution according to the standard autporities. The main sources of information are listed in the Bibliography on p. 125.

THE BRITISH FERN COLLECTION IN THE NATIONAL MUSEUM OF WALES

The history of the Herbarium of the National Museum of Wales has been briefly recorded in Welsh Flowering Plants. The collection of British ferns, on which this guide is based, comprises some 2,200 specimens; these have been acquired from a variety of sources, gifts coming first in order of import­ ance: the principal items under this heading include the W. A. Slioolbred Collection (a bequest which is especially rich in Monmouthshire specimens) and the T. G. Rylands Collection (which was transferred from Warrington Museum in 1927, and includes many North Wales specimens). Here also should be mentioned the many-mostly small-donations of specimens collected in Wales specially for the Department. During the years 1913-53, 1,180 specimens were contributed by over seventy donors most of whom are referred to individually in the list of collectors on p. 123.

In addition, departmental collecting has yielded 234 sheets, certain collections have been purchased entire and other specimens have been received in exchange.

t Records of plant distribution in Great Britain are still kept on the 'county' basis which was first devised by H. C. Watson over a century ago. A statement that a certain species occurs in a particular county or similar area (vice-county) may mean only that a single specimen was once found there or it may mean that the species is common all over the county. The 'county record system' therefore is obviously imp~rfect but no better method of recording plant distribution has yet been put into practice over a wide area.-County records which lack confirmation are indicated by square brackets. PLAN OF TEXT 31

PLAN OF THE MAIN TEXT The main text is set in the framework provided by Christen­ sen'$ FiUcinae .' this author's descriptjons of the larger groups (suBclasses down to subfamilies, and in some instances down to genera) have been given throughout as nearly as possible in his own words, subject however to two limitations. First, -certain technical terms and expressions have been replaced or modified by the use of less unfamiliar words; second, micro­ scopic characters and details relating to the gametophyte generation have been as far as possible omitted. The explanatory notes inserted here and there (usually at the ends of the families) are based for the most part on Bower's Filicales,' they indicate briefly how his criteria have been applied, and with what results; and serve usually to justify the order in which the families and lower- groups have been arranged. Christensen, however, does not agree with or act upon all of Bower's conclusions: important differences of opinion between the two authors have. therefore been men­ tioned wherever necessary. The core of the book is contained in the descriptions of the species; here the authors are under a profound debt to the . classic writers in tb.is field, notably Luerssen,. but nevertheless every Vv' eIsh species has here been described anew from the specimens themselves; and in order to increase the usefulness of the work brief descriptions of the remaining British species have also been added. Each specific description is followed by a note on the kind or kinds of habitat in which the plant is found in Walcs and of its distribution in Wales and elsewhere (see p. 30); detailed references to specimens in the Herbarium are given for all but the very common species. Brief descriptions of any important varieties are also appended. This book will it is hoped be used frequently for the identifi­ cation of specimens in the field. This has been facilitated in two ways: first by printing the most distinctive characters in italics: secondly by the provision of a complete series of keys, those to the species being placed under the headings of the respective genera, while a key to the genera themselves follows immediately at the end of this Introduction. These keys however are only of use as pointers: the reader should always check his identifications by reference to the complete descriptions. 32 INTRODUCTION

All measurements, in accordance with modern usage, are given in metric units, usually in centimetres (cm.) but some- . times in millimetres (Imm. = y\ycm.) .or metres (lm. = lOOcm.). For the convenience of readers who are not familiar with this system scales, of centimetres and inches are printed side by side on the back of the cover. The dimensions of rhizomes are given as length X diameter; the height only of fronds is stated; the size of the blade is quoted as length X breadth. The normal range of a particular dimension is usually indicated; sometimes the size attained by unusual specimens is also added in brackets.

HINTS TO COLLECTORS Collecting ferns presents no special difficulties, but care must be taken to gather fronds which are well matured. They need not necessarily be the largest, but should show ripe sari. Immature fronds are usually misleading and should be avoided~ . or if collected should be accompanied by mature ones. The scales which clothe the base of the stalk often provide charac­ ters of importance in identification, so the fronds should be collected complete with the stalk, i.e. they should be detached from the root-stock at the point of attachment thereto. This can be easily accomplished with most ferns by gripping the base of the stalk and applying a firm· downward pressure, so breaking it away from the root-stock. It is not necessary to collect complete fern plants, and they should never be uprooted. 33

ARTIFICIAL KEY TO THE GENERA OF WELSH FERNS In this key the group 01 genera included within paragraph A is contrasted with group AA. Next, group A is divided by means of other contrasting characters into groups B and BB ; arid AA is similarly treated. Each of the groups R, BB, etc., is then sub~divided where necessary until finally the contrasted groups consist of single genera.

A Water fernR B Leaves rush-like 4. PILULARIA, p. 46 BB Leaves moss-like '22. AZOLLA, p. 119 AA Land ferns C Leaves filmy in texture (Hymeno­ pbyllaceae) D Receptacle bristle-like projecting from the indusium " 6. TRICHOMANES, p.53 DD Receptacle included within the indusium 5. HYMENOPHYLLUM, p.49 CC Leaves firm in texture E Fertile frond or portion of frond distinct from stedle frond F 'young fronds straight in the bud (Ophioglossaceae) G Sterile blade and fertile spike both simple 2. QPHIOGLOSSUM, p.40 GG Sterile blade pinnate, fertile spike branched 1. BOTRYCHIUM, p. 38 FF Young fronds circinate in the bud H Upper pinnae only fertile, lower ones sterile and leafy 3. OSMUNDA, p. 43 HH Fertile frond bearing sari throughout, and ~ntirely distinct in appearance J Frond tri- or quadri-pinnate 8. CRYPTOGRAMME, p.57 J J Frond simply pinnate 10. BLECHNUM, p. 62 EE Fertile and sterile fronds similar in appearance K Sori marginal covered by the incurved edge of the frond L Sori in a continuous marginal line covered by a con­ tiuuous indusium 7. PTERIDIUM, p. 55 LL Sari separate covered by distinct lappets of the frond margin. 9. ADIANTUM, p. 59 KK' Sari superficial 34 WELSH FERNS

M Indusium present (in the young condition at least) N Sori nearly circular o Indusium inferior P Indusium surrounding the base· of the 50ruS and entirely lacIniate 16. WOODSIA, p. 85 pp Indusium almost en­ tire, at first hood­ like 15. CYSTOPTERIs, p. 82 00 Indusium superior Q Indusium reniform R Sari large, indusium persistent 17. DRYOPTERIS, p. 90 RR Sori small, indus­ ium small deci­ duous 19. THELYPTERIS (species 1-2), p. 107 QQ Indusium circular .. 18. POLYSTICHUM, p. 100 NN Sari oblong or linear (may be very short) S Sari oblong reniform 14. ATHYRIUM, p. 79 SS Sori linear T Sari paired, indusia of each pair opening towards each other 11. PHYLLlTIS, p. 64 TT Sori single, indusium opening towards the central vein or midrib 12. ASPLENIUM, p. 66 MM Indusium absent or 'appar­ ently absent U Sori linear, frond densely covered with scales beneath 13. CETERACH, p. 77 VU Sari circular, frond glab­ rous or somewhat hairy or scaly beneath V Fronds becoming disarM ticulated from the rhizome 21. POLYPODIUM, p. 117 VV Fronds becoming disarM ticulated if at all some distance abpve the rhizome KEY TO THE GENERA 35

W Fronds not becoming disarticulated X Frond pinnate, with pinnatifid pin­ nae 19. THELYPTERIS (species 3) J p. 107 xx Frond bi- to tri­ pinnate 20. GVMNOCARPIUM, p. 113 WW Fronds becoming disarticulated at or about half-y.ray 16. WOODSIA,'" p. 85

* This genus is repeated here in order to allow for the possibility that its indusium may not always be recognised as such. DESCRIPTIVE CATALOGUE OF WELSH FERNS

Cla'Ss FILlCINAE (Ferns)

Su bclass I. Filices Eusporongiotoe Sporangium arising from a group of cells, its walls consisting of several layers of cells. Spores all of the same kind.

Order Ophloglossal·es Characters, those of the only family:

Family OPHIOGLDSSACEAE Terrestrial (rarely epiphytic) herbs with short, fleshy, usually naked (never scaly) stock 'and fleshy roots. Leaves one to several, each divided deeply into two portions set one behind the other on a common stalk, the hinder part forming the sterile leaf-blade, the nearer part the fertile spike, the whole folded or bent in the bud but not rolled up circinately, and protected by the *ochrea-like sheathing base of the last preceding leaf. Sporangia borne in two rows on the margins 'of the fertile spike or its branches, sessile or on a very short, thick, stalk, and without an annulus. Spores very numerous (up to 15,000). Frothallus as a rule living completely under­ ground, tuber-like in appearance, usually without chlorophyll and nourished from decaying matter in the soil, 'i.e. sapro­ phytically, through the agency of a fungus living in the cells of the pro thallus (mycorrhiza) .-;3 genera with about 80 species.

'" Ochrea (Lat. a greave), a tubular stipule or pair of stipules so combined (J ackson); in flowering plants seen, c.g. in the genus Polygonum. 38 BOTRYCHIUM

The Ophioglossaceae are not found as fossils and are 8ifficult to relate to other families. The fertile spike (their most peculiar feature) may have been formed by the fusion of a lower pair of fertile pinnae. The stalked sporangia of Botrychium are somewhat similar to those of some Palaeozoic ferns (Coenopteridaceae, p. 25); and the family as a whole is probably related to other living ferns only through Palaeozoic ancestors.

Genus I. BOTRYCHIUM Sw. Moonworts Sterile blade entire or pinnately lobed or up to 3-4 times pinnate; fertile spike simply pinnate or more highly branched. Sporangia free, sessile, arranged in two rows one on either side of the spike or segment and opening by a transverse slit. Small terrestrial herbs with a short, brown, upright, fleshy, usually unbranched subterranean stock, which is sheathed in the dry bases of old fronds and produces eacb year as a rule a single frond, the base of which is surrounded by a conspicuous membranous and stipule-like sheath derived from the frond of the previous year, and which is borne on a thick, fleshy stalk.-About 40 species, chiefly in the Arctic and North Temperate zones (especially North America), a few in the Tropics and Antarctic.

BOTRYCHIUM LUNARIA (L.) Sw. Moonwort (Fig. 17.) stock subterranean, upright, usually unbranched, cylin­ drical, brown, beset below with thick fleshy, radiating roots. Frond 5-1 5(25)cm. overall, taking three years to develop;· stalk about half or as long as the blade, surrounded at the base by long, brown sheaths formed from the persistent bases of old fronds, hollow and fleshy. Blade 3-1O(12)cl11., oblong, pinnate; pinnae (Fig. 14, G) 4-7 pairs, fan-shaped to crescent· shaped, their margins entire or slightly and irregularly crenate or (in the variety subincisa Roeper) deeply crenate ; venation Cyclopteridian. Spike 2-10(16)cl11., its stalk in well­ developed specimens often overtopping the sterile blade, pinnate to bipinnate. Sporangia borne on the margins of the ultimate segments, golden brown when mature. Abnormal forms with two fertile branches or with capsules on the edges of the sterile fronds are occasionally met with. Pastures, hillsides, heaths, and fixed sand-dunes. Easily overlooked and probably much commoner than records suggest. B. LUNARIA 39 First recorded in 1606-08 by Sir John Salusbury: MS. record in his copy of Gerard's H eI'bal now in the Library at Christ Church, Oxford. * 'Lunaria minor is found in Cunnygree of the Right Hon. Sir John Salusbury, Knight, lying between Botuarry [Bodfari] and Carewis and great plenty of them are found in Place y Chambers fielde lying hard by Snodinge parke neare Denbigh.' Recorded from every county in V\Tales. Throughout the British Isles. Bipolar. In the Arctic and Northern Temperate and Antarctic and South­ ern Temperate regions. Europe, except in the coastal parts of the Mediterranean region and in the Hun­ garian plain. \iVestern and northern Asia to Japan. HimaJaya. South Australia. Tasmania. New Zealand. Greenland and North America from Alaska to Newfoundland, south to southern California, Minnesota and Vermont, South America in Chile and Patagonia. Specimens in Hel'barium.-Mon.: Twyn-Gwyn Dingle, PontypooJ, T,H,T" 1853; Mounton,. W.A.S., 1894. Clam.: Kenfig, E,L.D., 1904 and E.M.T., 1941; nr. Nottage, E.M,T" 1930. Carm.: Llandovery, H.H.K., 1907. Pemb.: Plumstone Mountain, E.C.H., 1933; Nevern, J.A. Whe,. 1941. Card.: Towyn \y'arren, J .A.Whe., 1941. Mer.: Morfa Harlech, D.A.J., 1903. Caern.: nr. Bangor, C.W., 1876 and G.H,B., 1900. Denb.: nr. Wrex­ ham, C.\Va., 1920.

Var. SUBINCISA Roeper. Margins of· the pinnae deeply crenate. Recorded from Anglesey. Specimen in Herbarium.-AngI.: Aberffraw Common, ] .E.G" 1882.

Fig. 17. Moonwort (Bot­ rychium Lunaria), one­ * See Gunther, R. W. T.: Early half natural size. British Botanists. Oxford, 1922, D 40 OPHIOGLOSSUM

Genus 2. OPHIOGLOSSUM L. Adder's Tongues Sterile blade usually simple and linear to ovate in outline with an entire margin, but in some species forked or palmately lobed, and in one (purely saprophytic) species absent altogether; fertile spike usually simple but sometimes forked or pinnately branched; sporangia lq.rge, sunken, fanning two closely set marginal rows one on either side of the midrib ; dehiscence by transyerse slits. Small terrestrial herbs with short, upright, unbranched, stock usually growing underground and bearing one or several fronds.-About 50 species, mostly local but together covering all regions (some larger epiphytes in the Tropics).

OPHIOGLOSSUM VULGATUM L. Adder's Tongue (Fig. 18.) Stock underground, short, upright, covered above by the bases of old fronds and beset below with thick fleshy hori­ zontal, usually unbranched, roots, some of which elongate like stolons and produce at the apex buds from which new plants arise. Fronds solitary or rarely two or three, (4)8-30(45)cm. overall with a hollow free-standing base enclosing a bud which will give rise to next year's frond; common stalk up to 15(18)cm. more or less half underground. Blade 2-12(15) x I-S·5cm., ovate or ovate-lanceolate, its apex obtuse or subacute, glabrous, fleshy, easily wilting; venation: an inconspicuous but more or less straight mid-vein with a network of veinlets, the coarser meshes enclosing finer ones and some free-ending venules. Fertile spike simple, usually much overtopping the sterile blade 2-15(27)cm. X 0·2--Q·3cm., the upper fertile portion I-S(7)cm. bearing 16-40 sunken sporangia on either side and ending in a drawn-out sterile point. Occasional to frequent in meadows, pastures, and damp sandy ground. First recorded in 1606--08 by Sir John Salusbury: MS. record in his copy of Gerard's Herbal now in the Library at Christ Church, Oxford. * 'The Herbe Addertongue groweth likewise in the lower end of Ravenscroftes field [nr. DenbighJ.' Recorded from every county in Wales.

* See footnote, p. 39. · O. VULGATUM 41

Fig. 18. Adder's Tongue (OPhioglossum vul~ gafum) , two~thirds natural size. On the right: portion of fertile spike (x 5). 42 OPHIOGLOSSUM

Specimens in Herbarium.-Mon.; Barnets Woods, W.A.S., 1893; St. Arvans, RS.H., 1894; nr. Monmouth, S.G.C., 1935; nr. Henllan, Llanthony Valley, S.G.C., 1940; Hadnock, S,G.C., 1941; Slade Wood, J.C.E.,1943. Glam.: nr. Llanmadoc, H.J.R., 1905; Cwmcidy, Barry, H.J.R., 1908; nr. Lavernock, A.E.W., 1921 ; Newton, KM.T., 1930; nr. Moulton, M,L., 1932. Carm.: Llandovery, H.H.K., 1907. Pemb.: Camrose 'iVood, KC.H., 1931. Caern.: Penrhyn Park, C.W., 1877; Bangor, ].E,G., 1882 and G,R.B., 1925. Throughout Great Britain and Ireland but becoming less frequent in Scotland. Circumpolar. In the greater part of Europe and extending north­ wards to Iceland (absent from the Russian Steppes). Madeira, Algeria, western, northern and eastern Asia. North America from Prince Edward Island to Alaska, south to Florida and vVashington, D.e. Var. POL YPHYLLUM BraWl Much smaller than the typical form. Fronds 2-3, 4-lOcm., all or 1-2 fertile, seldom all sterile; blade 1'5-3·5 X 0'5-1·3 cm., narrowly or broadly lanceolate, seldom ovate, usually acute, rarely obtuse. Spike 1-2 times as long as the blade with about 6-14 capsules on each side. Recorded from Merioneth. The specimens from Glamorgan do not appear to be correctly placed under this variety..

Specimens in Herbarium.~Mer.: Moria Harlech, D.A.J., 1902; nr. Dyflryn, J.H.S., 1931.

OPHIOGLOSSUM LUSITANICUM L. Included in most British floras on account of its occurrence in the Channel Islands. The plant is 10cm. high at the most, usually much less; the sterile blade is lanceolate to narrow-lanceolate and net-veined with no :fine secondary meshes and no included free vein-endings. Fronds appear in Novembel' (those of O. vUlgatum in June).

Subclass 2. Filices Leptosporangiatae Sporangium originating from a single superficial cell, its wall consisting of a single layer of cells. Homosporous or heterosporous.

Order I. FilicaJes Leaf circinate in bud. All, Marsileaceae excepted, homo­ sporous. Family I. OSMUNDACEAE Terrestrial ferns with massive, hard, erect stock, without scales. Leaves all of one kind, or fertile distinct from sterile, pinnately divided, their stalks widened at the base into OSMUNDA 43 broad flaps, which are covered with glandular hairs and protect the young parts; stalk and rachis often with woolly hairs; veins free. Sporangia either marginal on much reduced segments (Osmunda) or superficial on the under side of unaltered pinnules (Todea and Leptopteris) , not forming real sori and without indusium, an developing simultaneously ('Simplices'), large, globose or pear-shaped, short-stalked and with a rudimentary annulus formed by a few thick-walled cells at the back, dehiscent by a slit running from these cells across the top and down the front to the stalk (cf. Fig. 19). Spores rather llumerous (up to 500).- 3 genera with about 20 species.

Fig. 19. Sporangia of Royal Fern (Osmunda regalis). Left: from one side; middle: from behind showing the annulus; right: from the front. (X 50.) (After Luerssen.)

If Bower's criteria (p. 22) be applied to the Osmuudaceae the family' can be shown to be primitive in almost every respect. This conclusion is confirmed by the evidence of geology, Unmistakably Osmundaceous stems occur as fossils as far back as the Permian: in particular these ancient plants possessed the upright stock surrounded by leaf bases with broad flaps still seen in the Royal Fern of to~day. Numerous sporangia closely resembling those of living Osmundaceae have come down to us from the Coal Period.

Genus 3. OSMUNDA L. Fertile leaves or pinnae distinct from the sterile ones and more richly branched than they, the sporangia confined to the upper or middle part of the frond or occupying the whole of it and borne on ultimate segments which are reduced in width to skeletons having no normal leaf tissue, and so appear like rows of tassels on the pinnae of the next higher order.-12 species. Handsome ferns found chiefly in swamps in the Temperate and Tropical regions, mainly of the Northern Hemisphere. 44 OSMUNDA

OSMUNDA REGALlS L. Royal Fern (PI. 1, Figs. 19, 20.)

Stock short, upright, branched, clothed in a tangled covering formed by the densely set persistent bases of old leaves and the numerous much branched black roots, the whole forming a rounded ball-like mass up to 30cm. in diameter. Fronds BO-IBOcm. tufted, in a closely set spiral, the outer ones sterile, curved and nodding outwards, the inner ones fertile, upright; stalk in the purely sterile leaves i-t, in the fertile ones up to as long as the blade, dark-coloured and winged below, the wings broadening out into broad membranous flaps, the stalk otherwise (like the channelled rachis) yellow­ -green to yellowish, in the very young stage densely covered with yellow-brown cobweb-like hairs, later glabrous. Blade 40-120 X up to 40cm., lanceo­ late in outline, bipinnate (fer­ Fig. 20. Royal Fern (Osmunda tile portion when present regalis). Single pinn ule tri-pinnate); primary pinnae about natural size. usually 7-9 on either side, up to 30cm., opposite or nearly so, set rather wide apart at an acute angle to the rachis, shortly stalked, oblong, acute, pinnate; the pinnules on the side of the pinna directed toward the apex of the frond somewhat shorter than the others; sterile pinnules 7-13 on either side, 2·5-B·5cm., wide apart, sessile or nearly so, oblong or 0 blong­ lanceolate, obtuse, unequal and often lobed at the base, the margin shallowly serrate; venation Neuropteridian, the ultimate veinlets usually running into the bays between the serrations. Fertile leaves usually with 2--3 pairs of sterile pinnae below followed by 7-14 pairs of fertile pinnae of gradually decreasing length, only the lowest 3 or 4 of which are again pinnate; ultimate fertile segments very narrow, more or less completely covered with the clustered sporangia. 'Frequently the lowest fertile pinnae are sterile and more or less leafy toward the apex or almost to the base. Spomngia pear'shaped. Bogs, marshy ground, marshy copses and borders of damp woods. Rare in Wales and now extinct in many of its former localities. Plfl,te ]. ROYAL T"ERN (OS1rl'll11da y~galis) complete frond (X l) ) I / I (

Plate 2. Above: KILLAR~EY :FERN (Trichomanes speciosu111) and PARSLEY FERN (Cryptogl'amme crisjJa) (sterile and fertile -rronds) Below: MATDENHAIR FERJ'; (Adianhrm capiltus-veneris) O. REGALIS 45 First recorded, 1670; Ray, Cat. Plant. Ang., 113. 'r have observed it in boggy places ... in Wales.' Recorded from every county in Wales. Throughout the British Isles, but unrecorded for several counties in the east of Scotland. Throughout the forest zone of northern Eurasia (except northern Scandinavia and ? Poland) streaming (though with interruptions) through the Tropics to southern India and via the Azores, Abyssinia and Central Africa to the Cape and the ::v.Iascarene Islands. '" Similarly in North America extending south via Mississippi, Florida and West Indies into South America. Specimens in Herbarium.-Mon.: Cwmbran, T.H.T., 1852; Shire­ newton, W.A.S., 1898. Glam.: Sketty, C.l-I.B., 1848; Llangynwyd, E.N.M,T., 1921; Oxwich, H.A.H., 1924; Penllergaer, M.H.N., 1928; Crymlyn Bog, H.A.H., 1939; nr. Neath, E.M.T., 1941 ; Rhyd~y-pandy, J.A.W., 1941; Clyne Common, A.E.vV. and J.A.W., 1944. ,Brec.: above Ystalyfera, V.M.P., 1930. Carm.: below Craig Twrch, H.H.K". 1907; nr. Cross Hands, C.W.B., 1926. Pemb.: nr. Haverfordwest, R., 1857; nr. Amroth, G.~.W., 1911 and J.E.A., 1925; Tenby, J.E.A., 1926; Clarbeston Road, ].E.A. Card.: Tregaron Bog, H.A.H., 1936. Mer.: between DolgeUey and Barmouth, C.VV·., 1876; Bontddu,] .A.v"., 1941. Angl.: nr. Ty-croes, ].E.G., 1881.

Family 2. MARSILEACEAE Aquatic or semi-aquatic herbs with long, creeping, branched, hairy rhizomes. Leaves in two rows, circinate in bud, undivided and subulate (Pilularia) or 'with 2-4 pairs of clover-like pinnae (Marsilea and Regnellidium). Sporangia borne in enclosed structures called sporocarps which are interpreted as highly specialized pinnae. The sporocarp (Fig. 21) is a hairy, firm, more or less spherical body which when ripe ruptures by 1 or 4 slits. Sari four to several, each enveloped by a mantle (called the indusium) and consisting of a number of sporangia borne on a receptacle which is situated on the outside wall of the sporocarp. Sporangia of two kinds: megasporangia, situated below, each containing­ one very large megaspore, and microsporangia, situated above, each containing numerous rnicrospores.-3 genera with about 70 species. The family W3.S formerly grouped with the present Salviniales (cf. p. 119) under the heading Hydropteridales, the most important features in common being the semi-aquatic habit and the possession of two kinds, of spores. These characters, however, might well have arisen independently; in many other respects the Marsileaceae (though not the Salviniales) rro:semble the Schizaeaceae (an ancient family of terrestrial fel'l1S now found chiefly within the Tropics) and the systematic position of the Marsileaceae has been altered accordingly.

'" Madagascar, Mauritius, Bourbon, Seychelles and Comoro Islands~ 46 PILULARIA

Genus 4. PILULARIA L. Pi/Iworts Leaves rush-like, witho,llt pinnae, each bearing one spherical pill-like sporocarp (hence the name) with 2-4 vertical com­ partments, each containing a sOIus and splitting longitudinally when ripe, liberating the sporangia in a drop of rnucilage.- 6 species in Europe, America and Australia.

Fig. 21. Sporocarp of PUwort (Pilularia globulifera) seen in (approximately) vertical secti.on showing two of the four compartments. The sp:)fangia are produced in sari, micro­ sporangia above and rnegasporangia below. (x 20.) (From Luerssen in Rab. J{rypt. Flora, Vol. Hi.)

PILULARIA GLOBULlFERA L. PiI/wort (Figs. 21, 22.) Rhizome cylindrical, up to 50cm. long and i·5mm. in diameter (nsually much less), creeping or free floating, curved upwards at the tip. Leaves narrow and subulate, 3-iOcm. X about imm., circinately coiled in the bud, cylindrical, thread­ like, glabrous, fresh green, crowded to distant (O·4cm. to 2·Ocm. apart), arising alternately from the upper surface of the rhizome; close to the base of each are a root and a bud which grows into a branch shoot. Sporocarps (in 'fruiting' specimens) borne one at the base of each leaf on a stalk P. GLOBULIFERA 47 O·S-I·Omm. long, spherical (2·S-3·Smm. in diameter) and covered with a dense mat of hair, yellowish-green at first, changing to light brown and finally brownish-black;' internally divided into four vertical compartments each con­ taining a single SOIUS which comprises a swollen ~eceptacle

Fig. 22. Pillwort (Pilularia globulifera) , natural size. together with numerous microsporangia (in the upper half) and fewer (13-25) megasporangia below. Both kinds of sporangium sessile (some elongated cells near the tip of each may be vestiges of an annulus); megasporangia mostly ovoid or obovoid; microsporangia narrower, elongated obovoid to club-shaped, both kinds usually somewhat laterally com­ pressed. The internal tissues of the sporocarp become 48 PILULARIA mucilaginous when ripe and swell in the presence of water; the shell then breaks into quarters liberating the sporangia. Mud or damp ground beside pools and lakes, or free floating in standing water. Rare. First recorded, 1796; Griffithin Withering, Arr. Brit. Plants, ed. 3, 3, 760. 'About 2 miles from Mold, on the north side of the Chester road, near Clawdd Ofia, or Offa's Dyke.' Recorded from every county in Wales except Mon. and Carm. Throughout Great Britain, becoming rarer in the south~east and in the north of Scotland. In Ireland only in the north-east and in south Kerry and Galway. Western Europe from southern Scandinavia to Portugal; scattered in central and southern Europe and extending to southern Russia. Specimens in Herbarium.-Glam.: nr. Cowbridge, H.] .R, 1904; Myuydd y Glew, A.E.W., 1920. Brec.: Pant-y-llyu, A,R.W., 1928. Had.: nr, Llanbwchllyn, A.E.W., 1928. Pemb.: St. David's, M.B., 1923, K.M.G., 1927. Caern.: Afon Wen, J.KG., 1890; Llyn Idwal. H.A.H., 1925. Denb.: Llyn Chwythlyn, A.A.D. and A.W., 1925. Flint.: Llyn Helyg, A.A.D, and ] ,A.Wh., 1906, AngJ-.: Ty-croes, J.E.G.

Family 3. HYMENOPHYLLACEAE. Filmy Ferns Minute to medium-sized terrestrial or epiphytic herbs. Rhizome mostly widely creeping, slender, and branched, with leaves in two rows' and with few roots or none. Leaves almost invariably very thin and tr~nslucent, composed usually of a single layer of cells and without stomata; often with simple or branched hairs, but without scales; in the Welsh species divided into narrow segments each supplied with a single vein (Coenopteridian venation). Sari marginal on the endings of veins, which project beyond the leaf margin into the club-shaped or bristle-like receptacle; indusium a flask-shaped cup or a two-valved pocket which encloses the base or the whole of the receptacle. Sporangia (Fig. 23) arising in gradate succession, short stalked, globose at com­ pressed, provided with an oblique annulus and opening laterally by a long slit. Spores few to many.-4 genera with over 600 species. The Filmy Ferns are probably descended from ancestors of more typically fern-l\ke appearance: their filmy character is an adaptation to moist conditions, Their stems-notably in the least specialized species-possess a very simpJe form of skeleton which resembles that of HYMENOPHYLLUM 49 • the Botryopterideae, a very ancient and primitive family of ferns, which are found only in the Coal Measures and older rocks. The sari are strictly' marginal, a character which links the family on the one hand with the Ophioglossaceae and on the other with some tree ferns (viz.

Fig. 23. Sporangium of a filmy fern (HymenophYllum tun­ brigense). Left: showing the stomium; middle: the same sporangium turned through about ninety degrees to the left; right: the same from the side away froin the stomium.' (After Luerssen.) the Dkksoniaceae) and the bracken-like ferns (pteridoideac). The' sporangia develop one after the other on the receptacle, from its apex downwards, whilst the receptacle itself continues to elongate: the sari are thus markedly gradate and the family is in this respect at an intermediate stage of evolution between the most primitive and the most advanced forms.

Genus 5. HYMENOPHYLLUM Sm. Filmy Ferns Indusium deeply divided into two valves or lips (Fig. 24). Receptacle included inside the indusium (not projecting beyond it as in Trichomanes) . Small delicate ferns of Fig. 24. Ripe sarus of Tunbridge very uniform appearance, Filmy Fern (Hymenophyllum tun· closely resembling the leafy b'ligense) showing the two lips of liverworts and mosses; the indusium, one of which has rhizome usually thread-like, been slightly bent back in order to display the sporangia (about creeping; fronds in two X 16). rows, erect prostrate or • 50 HYMENOPHYLLUM pendulous, usually crowded to form cushion-like masses, dull brownish-green, translucent, simply or bi- to quadri-pinnatifid, the lobes narrow, elongated and ribbon-like.-About 300 species. Chiefly in Tropical rain forests, extending far in to the South Temperate zone, some few reaching as far north as Japan on the east and the Atlantic coasts of Europe on the west.

KEY TO SPECIES Pinnules spreading, their veins ending slightly short of the margin; margin of the indus~ iu"m irregularly toothed 1. H. TUNBRIGENSE Pinnules recurved, their veins extending to the margin; margin of the indusium entire 2. H. PELTATUM

I. HYMENOPHYLLUM TUNBRIGENSE (L.) Smith Tunbridge Filmy Fern (Figs. 24, 25.) Fronds stalked, 2·5-11·5cm. long, more or less regularly divided on either side of the rachis into rhomboid or linear­ rhomboid flat spreading segments, having spinulose teeth near the apex; veins ending slightly short of the margin. Sori developed mostly in the upper half of the leaf and in the angles between the main lobes and the axial portion of the lamina. Indusium a flattened pocket, slit! of the way down into two orbicular valves which are irregularly toothed on their upper edges. In mountainous districts on moist shady acidic rocks and rock ledges, more rarely on tree trunks. Rare or local. First recorded, 1724; Dillenius in Ray, Syn., ed. 3, 123. , ... on the left Hand as SOon as you enter the Mountains to go to the old castle, near Lhanperis [Llanberis, Caern.]'. As the two British species were not distinguished until long after Dillenius' day, the record is ambiguous: it may refer either to Hymenophyllum tunbrigense, or to H. peltatum ,which grows abundantly below Dolbadarn Castle (the 'old castle' referred to). Distribution in Wales: Glam., Brec., Carm., Card., Mer., Caern. On the western side of Great Britain northwards to the Inner Hebrides; in Ireland chiefly in the south and north-west. H. TUNBRIGENSE 51

Cosmopolitan but markedly discontinuous. The Atlantic fringe of Europe, with small autliers in Germany and the :rvlediterranean (Corsica and Central Italy). Atlantic islands. Temperate Australia. Tas­ mania. New Zealand. Mauritius. South Africa. Jamaica. South America (Venezuela, Brazil and Chile).

Fig. 25. Tunbridge Filmy Fern (Hymenophyllum tUnbrigense), rather more than twice natural size.

Specimens in Herbarium.~Glam.: Dimbath Valley, E.M.T., 1932. Brec.: Hepste, P.W.R., 1927. Carm.: Llandybie, H.H.K., 1907; Llangadock, nr. Llandovery, J.'F.J., 1931. Card.: Cwm Einon, P.W.R., 1944. Mer.: Cennant, Llenyrch, D.A.J., 1898; A.W., 1931. Caern.: Bettws-y-coed, J .E.G., 1880. 52 HYMENOPHYLLUM

2. HYMENOPHYLLUM PELTATUM Desv. Wilson's Filmy Fern (Fig. 26.)

Fronds very similar in most respects to those of H. tun­ brigense, but more rigid, of a somewhat darker green and recurved at the- tip and margins, whereas those of H. tunbrig­ ense are flat; main lobes of the lamina sometimes un­ divided or, if divided, the resulting segments situated on the sides of the lobes toward the apex of the frond, giving the lobes a one-sided appear­ ance*; veins extending to the tips of the segments. Indusium more ovoid than in H. tun­ brigense and projecting from the margin of the frond so as to appear stalked; margins of the valves entire. Grows in similar situations to the last species, but much more frequently; the two are sometimes found growing together. First recorded 1830; Hooker, Brit. Flora, ed. 1, I, 450. 'Wales.' Distribution in Wales: Glam., Brec., Rad., Carm., Fig. 26. Wilson's Filmy Fern (Hymeno­ Pemb., Card., Mer., pkyllum peltatum). rather more than Caern., Denb., twice natural size. [Ang!.].

,. Such one-sided lobes occur in H. tunbrigense, especially in the upper part of the frond: but in that species the lowest lobes are equally divided whilst in H, peltatu~ all the lobes are unilateral. H. PELTATUM 53

In the south-west of England and throughout the mountainous districts of Great Britain and in the greater part of Ireland. Cosmopolitan. Farces. Western Norway. North-western France. Atlantic Islands. * Reunion. South Africa. Tasmania. New Zealand. Temperate South America (Chile and Cape Horn). Specimens in Herbarium.-Glam.: Melincourt waterfall, E.Y" 1849 ; Craig y llyn, A.E.W., 1920; Dimbath Valley; KM.T., 1930; Padell y bw1ch, B.A.W., 1937. Brec.: Hepste Glen, W.A.S" 1896 and L.N., 1944; Ystradfellte. H.A.H., 1925; Craig Gledsiau, P.W.R., 1927; Abergwesyn, A.E.W., 1929; Pont Rhyd Gach, Llwch Valley, F.H.B.M., 1934. Carm.: Cwm Llaeth, H.H.K., 1907; Ystradffin, J.F.]., 1931. Pemb.: nr, Tre-cwn, R., 1856; Treffgarne Rocks, E.C.H., 1931. Card.: Llyfnant Valley, ] .H.S., 1922; Nant Berwyn, Tregaron, ] .H.S., 1937. Mont.: Llyfnant Valley, ].A.\V., 1941. Mer.: Dolgelley, G.H.B., 1884; nr. Barmouth, E.P., 1905; Ffestiniog Valley, W.C.B., 1922; Arenig Fawr, A.W., 1929. Caern.: nr. Conway, W.W., 1849; Twll-du, C.W., 1876 and ],E.G., 1883; Aber Waterfalls, G.H.B., c. 1890; Capel Curig, W.A.S., 1912; Eettws-y-coed, G.H.B., 1915; Cwm Idwal, H.A.H., 1924; Cwm Cywion, C.M.L., 1926; nr. Talybont, A.W .• 1929.

Genus 6. TRICHOMANES L. Indusium tubular, flask-shaped or bell-shaped. its margin either indistinctly bivalved or entire. Receptacle thin, elongated and bristle-like, pro­ jecting beyond the indusium (Fig. 27). Ferns similar iri general ap­ pearance to Hymenophyllum but of firmer texture and vary­ ing greatly in size and develop­ ment.-About 330 species, nearly all Tropical.

TRICHOMANES SPECIOSUM Willd. (T. radicans Sw.) Kil/arney Fern. Bristle Fern (PI. 2. Fig. 27.) Rhizome creeping extensive­ Fig, 27. Killarney Fern (Tri .. ly over the substratum, rela­ chomanes speciosum), Portion tively strong, black, covered of primary pinna, showing a sorns with elongated bristle­ with dark-coloured. jointed like receptacle projecting from hairs. Fronds arising at inter­ beneath the cup-like indus­ vals of 0·5-,jcm. ; stalk· as long ium (about X 10). '" Azores, Madeira and Canary Islands, 54 l'RICHOMANES as or rather shorter than the blade, erect, wiry and winged above (as is the rachis). Blade 5-20 x 2·5-10cm., ovate­ lanceolate in outline, dark green, somewhat firm in texture, persisting for three years, pinnate; pinnae alternate to almost opposite, lanceolate, twice or thrice pinnatifid. Sorl situated on the margins of the upper pinnae, usually on the sides of the primary pinna-segments which face toward the apex of the pinna, and replacing the lowest secondary pinna­ segments. Indusium 1·5-2mm., narrowly bell-shaped. Receptacle (whenperfecl) projecting Smm. or more. On rocks by shady streams and waterfalls; extremely rare. First recorded, 1863; J. F. Rowbotham, ex A. M. Gibson, in Phyt., 2nd ser., 6, 608. North Wales. Confined to two or three localities in Caernarvonshire and Merionelh. Very rare in -the British Isles: only in north Wales, Westmorland, Kyntire, Arran and Ireland (chiefly south~west). PantropicaL France (Basse Pyrenees). Western Spain. Atlantic islands. 'japan. China. Burma. Himalaya. Tropical West Africa and the neighbouring islands. Polynesia including Hawaiian islands. Alabama and Mexico via West Indies to Ecuador and Brazil (Rio de Janeiro). Specimens in Herbarium.-Mer.: nr. Harlech, D.A.J., 1905. Caern.: Moel Hebog, J.E.G., 1891.

Family 4. POLYPODIACEAE Ferns of extremely diverse size and habit, the great majority of typically fern-like appearance with pinnately divided leaves which are normally constructed and finn in texture. Sori varying in shape and "position, with or without indusium, and as a rule 'mixed' in composition. Sporangia long stalked and provided with a vertical annulus which is incom­ plete in front, where it is replaced by a number of thin-walled cells defining the stomium; dehiscence transverse. Spores few, usually 32 or 64.-Includes more than 85 per cent of known living ferns and 33 out of the 40 species recorded in Wales. This; the most advanced and successful family of ferns, appeared relatively late in evollition, its oldest fossil remains ,dating from the Lias. It comprises several subfamilies which together make up the great bulk of the Mixtae, and most of which evolved independently from ancestors belonging to the Gradatae or even the Simplices. Of these subfamilies the Pteridoideae possess marginal sari with an indusium, and the remainder superficial sori with or without an indusium. P. AQUILINUM 55 Subfamily I. PTERIDOIDEAE Sori on or just within the leaf margin, as a rule in the form of continuous coenosori borne on a commissure connecting the apperent vein endings, protected by a linear (outer) indusium appearing to be formed from the reflexed leaf­ margin and also, in the only Welsh genus, by a 'thin inner indusium.-Terrestrial ferns with erect stock or creeping rhizome, with hairs or scales; leaves not jointed to the rhizome, pinnately divided, the veins free or anastomosing without free included veinlets.-12 genera, Bracken and its allies, the Pteroid Ferns, are to be regarded as derived.)rom ancestors related to the New Zealand tree fern Dicksonia antarctica, examples of which may be seen in fern houses in this country. In the Dicksoniaceae scales arc absent (as in Pteridium), the sori are borne at the ends of fertile nerves and stand along the margin of the pinna, the indusium is two-lipped, and the sporangia are formed succe:c;sively (gradate). A series may be traced illustrating the fusion of the row of distinct sori Lllto a conticuous marginal sorus and the corresponding coalescence of the row of two-lipped indusia to form an upper and a lower indusium. Traces of the gradate development of the sori remain in Pteridium and in some of its allies; in others the sporangia are mixed from the first.

Genus 7. PTERIDIUM Gleditsch Sari linear on a marginal receptacle. Indusia following the course of the sarus, the inner very thin, the outer thicker and somewhat wider, appearing as if it were a reflexed membranous fringe of the leaf blade.-l cosmopolitan species with many geographical subspecies.

PTERIDIUM AQUILlNUM (L.) Kuhn (Pteris aquilina L.) Bracken Fern (Fig. 28.) Rhizome* widely creeping and branching underground, somewhat flattened-oval in section up to 2-3cm ..diameter, brownish-black to black, covered with short jointed bluntly­ pointed rust-coloured to dark brown glossy hairs. Fronds produced as a rule singly in two rows along the rhizome; when mature Q·5-l·5(3)m. overall; stalk erect, up to about as long as the blade, swollen, spindle-shaped, black and hairy at the * The underground parts of bracken consist of shoots of two kinds, thick long shoots which grow deep in the soil, and thinner short shoots which arise thercfrom, grow up toward the surface and then turn parallel with it. Only the short shoots bear fronds; they are beset with leaf bases and with a dense covering of fine roots. See Smith: Trans. Bot. Soc. Edin., 30, p. 3, 19,28; and 'Vatt: New Phytol. 39, 401-423, 1940. E 56 PTERIDIUM

base, otherwise nearly semicircular in section, about lern. thick, channelled (as is the rachis) down the upper side, yellow­ green to straw-coloured and glabrous. Blade often very large, 30-110 X ZS-90cm., always more or less bent back, triangular­ ovate (less often oblong), bi- to tri-pinnate; pinnae sUb-opposite (except sometimes the upper ones), the lowest pair the longest, the lower pairs stalked, ovate or oblong-ovate to oblong, usually bipinnate, the middle pairs sessile, oblong to lanceolate, pinnqte (with pinnatifid pinnules), the upper pairs linear-lanceolate to linear, simply pinnate ; pin­ nules of the lower pinnae alternate, narrow-lanceo­ late, acuminate; ultimate segments sessile, set close together like the teeth of a comb, broad based and running together at the base, oblong to linear, often slight! y sickle-shaped, blunt, those of the lower and middle pinnae often Fig. 28. Bracken Fern (Pleridium aquilinum): portion of an ulti­ lobed at the base, all seg­ mate segment of the frond seen ments otherwise entire from below and magnified about margined, leathery iQ. tex­ 10 diam'eters. On the left the outer ture, shining green and indusium is shown in its natural position, fringing the margin and glabrous above, paler and reflex~d so as to cover over and more or less covered protect the young sporangia. On (especially on the midribs the right the outer indusium has been flattened out and the sporan­ and other veins) with gia have been removed so as to yellowish hairs below; anow the inner indusium to be seen. venation Neuropteridian. Sori as described above for the genus, running all round the margins of the pinnules; outer indusium always present, inner absent when leaves are barren, both fringed with hairs. Common and abundant on deep well-drained siliceous soils in woods, grass heaths, sand dunes, neglected pastures and hedgerows. First recorded, 1726; Dillenius, Diary of a Journey into Wales. Druce and' Vines, The Dillenian Herbaria, p. 1, 1907. 'Near Trawsfynedd [MerionethJ.' Recorded from every county in Wales. Throughout the British Isles. P. AQUILINUM 57

Cosmopolitan. From the Equator northwards into Arctic Europe (not so far north in Asia) and Sub-Arctic America; and southwards to New Zealand'.

Subfamily 2. GYMNOGRAMMEOIDEAE. Sori superficial, without real indusia but often protected by pseudo-indusia formed by the more or less modified leaf­ margin; sporangia mixed, mostly large, short stalked.­ Ferns of diverse habit, mostly terrestrial.-27 genera.

The Gymnogrammoid Ferns are all ali~;:e in possessing no true indusium and in having rather ill-defined sari which are aligned along the veins. They differ among themselves in the extent to which the fertile veins are occupied by the sari. Thus in Anogramma each sarus may occupy the entire length of its veinlet, while in the Parsley Fern (Cryp­ togramme) the sorus is restricted to the terminal portion. The'Maiden­ Bair Ferns differ essentially from the others in the group in bearing their sari on specialized lappets which are turned back beneath the main leaf surfaces. The Gymnogrammoid Ferns as a whole there'fore are a rather varied subfamily but all may be regarded as being descended from ferns , resembling the Royal Fern family (Osmundaceae) in which no. true indusium was present and the sporangia were not grouped into true sari ; a connecting link is supplied by the tropical ferns of the genus Plagio­ gyria in which the sporangia have an oblique annulus (cf. Cryptogramme, p. 58), the sari are borne on the veins and there is no indusium or even any refiexing of the leaf margin.

Tribe I. CRYPTOGRAMMEAE Sori borne on the apical part of the free veirrs, usually oblong, protected by the reflexed continuous leaf-margin. Rhizome creeping or ascending, scaly; fertile leaves or seg~ ments more or less distinct from sterile ones, bi- to quadri­ pinnate.

Genus 8. CRYPTOGRAMME R.Br. Fronds of two kinds (a) with narrow divisions and bearing sori (fertile frond), (b) with broader divisions and without sori (sterile frond). Sori situated on the vein endings and rounded or more or less elliptical in outline. Indusium absent, but sori covered when young by the recurved margin of the frond. Sporangium pear-shaped and shortly 58 CRYPTOGRAMME

stalked; the annulus sometimes obliquely placed.-A small genus of Seven species, occurring chiefly in the North Tem­ perate zone, one only in Wales.

CRYPTOGRAMME CRISPA L. (R.Br.) Parsley Fern (PI. 2, Fig. 29.) Rhizome 2-3 mm. thick, creeping or ascending, ,caespitose, scaly, covered with dead leaf-bases. Fronds tufted in a dense

Fig. 29. Parsley Fern (Cryptogramme crispa). Left: single pinna from sterile frond (x 5); middle: single pinna from fertile frond (X 5); right: fertile segment with its margin flattened out on one side to display the sari (x 9). spiral and very numerous. Sterile (outer) fronds 7-15cm.; stalk as long or twice as long as blade. Blade 4-7 x 3-5cm., ovate to triangular-ovate, obtuse, pinnate; pinnae 7-15 stalked to sessile, ovate, obtuse, deeply bi- or tri-pinnatifid; segments alternate, normally obovate-cuneate, obtuse to truncate at the apex with 2 toA teeth or lobes in the upper half; venation Coenopteridian, a single vein running into each tooth or lobe. Fertile (inner) fronds longer stalked, 11-30cm. overall, broadly ovate to lanceolate, obtnse, pinnate; pinnae 7-11, stalked, ovate, once or twice pinnate, the ultimate pinnules stalked, mostly linear (less often more or less ovate), obtuse, their margins membranous and strongly inrolled beneath at first; venation Eupteridian. Sori elliptical in outline, borne on the vein endings, at first distinct, but eventually appearing to form a continuous band running parallel with the margin of the pinnule. Sporangia sometimes with a slightly oblique annulus. C. CRISPA 59 Mountainous districts only: a pioneer plant on screes formed from non-calcareous rocks, seldom if ever on a stable substratum. Abundant in many places in Snowdonia, rare Qf local elsewhere in Wales, and extinct in some of its former localities. First recbrded, 1662; Ray, Itinerary In (Memorials, ed. E. Lankester, 171, 1846). 'On Snowdon hill we found that species of Adianthum floridum which we had before observed in Westmorland. I Distribution in Wales: Glam., Brec., Rad., Card., Mont., Mer., Caern., Denb. On Exmoor, and in the mountain districts of Wales, the north of England and Scotland; Ulster and Wicklow. Arctic~alpine. Throughout central and northern Europe, extending northwards to Lapland, eastwards into Siberia (Lake Baikal), west~ wards to Spain and southwards to Greece. Asia Minor and Afghanistan. Specimens in Herbarium.-Glam.: Padell y bwlch, J.A.W., 1923;. nr., Ferndale, H.H., 1926, I Brec.: Brecon Beacons, G.H.G., 1850. Mont.: Cwm Hyddgen, J .H.S., 1922; Llanynog, J .A.W., 1940. Mer.: Cader Idris, comm., P.W.R., 1920. Caern.: Snowdon, G.F., 1838; W.A.S.,' 1873; W.!., 1895; nr. Llyn Ogwen, C.W .• 1876; Nant Ffrancon, J .E.G., 1887; Cwm Idwal, W.A.S., 1912 and H.A.H., 1924; G1yder Fawr, C.V.B.M., 1919; Cribbyn, H.A.H., 1925; Carnedd Dafydd, H.A.H., 1926. Tribe 2. GYMNOGRAMMEAE Sori linear, following the course of the veins, sporangia scattered, large. Rhizome mostly erect or short creeping. Genus 8a. ANOGRAMMA link , Sori elongated to linear running the whole length of fertile veins of the second or higher order or only occupying the upper part of the veins: leaf margin qUite flat and indusium absent. ANOGRAMMA LEPTOPHYLLA (L.) Lk. A small winter annual (up to about IOem.) in ,general appearance somewhat reminiscent of Cryptogramme put the fertile leaves not so dearly distinct from the sterile ones, in particular the margins of the ultimate segments not recurved; both kinds of leaves bipinnatifid. Rhizome not developed, the species perennating by means of a tuberous prothallus. Jersey. Mediterranean region. Africa. Southern India to New Zealand. Central and South America.

Tribe 3. ADiANTEAE Characters those of the only genus :- Genus 9. ADIANTUM L.. Maidenhair Ferns Sori (Fig. 30) confined to special fertile lobes or lappets of the leaf margin which are reflexed beneath the leaf and 60 ADIANTUM

membranons when matnre, and each of which bears a gronp of parallel linear sori situated on a series of fine veinlets (or less often borne also on the leaf surface between the veinlets) ; indusium none, the fertile lobes themselves protecting the sporangia. Leaves undivided to several times pinnate; leaf stalk usually black, shining and brittle; lamina of delicate tex­ ture and bright green in colour, its segments usually more or less triangular in outline; veins usually ending blindly. A ,large genus, but a very natural one and clearly charac­ terized by its foliage.-Species about 200, mostly Tropical, especially in America.

Fig. 30. Maidenhair Feni (Ad­ iantum Capillus- Veneris): pin­ ADIANTUM CAPILLUS­ llule seen from below, showing the Cyc10pteridian venation and a series of four fertile VENERIS L. membranous lappets of the margin; the two lappets on Maidenhair Fern the left are shown in the natural position, refiexed be­ (PI. 2, Fig. 30.) neath the frond; the next has been straightened out to show Rhizome creeping, up to 5mm. the sori and the last has also thick, covered with narrow had the sori removed to show the ,vein endings. (Enlarged chaffy brown scales. Fronds rather more than 3 diameters.) up to 30cm., erect when small, drooping when large, closely placed in two rows; stalk about as long as blade, beset with scales at the base, otherwise glabrous (like the rachises), dark brown to purplish-black. Blade up to 15 X IOcm., ovate or elongate-oval in outline, obtuse, bipinnate (simply pinnate toward the apex and in very small examples throughout); pinnae widely spaced and alternating on the rachis, stalked; pinnules np to 12mm. broad, on very fine hair-like stalks, obovate or elongate­ obovate and with a wedge-shaped base (less often practically rhomboidal or semicircular), the outer margin more or less deeply cut; venation Cyclopteridian. Fertile pinnules more or less truncate at the apex; lappets as described above for the genus, half-moon shaped, each about 3mm. wide by Imm. deep or smaller, 2-6 on each leaf segment. Sori 2-10 per lobe. A. CAPILLUS-VENERIS 61

Very local in sheltered places on sea cliffs, usually on calcareous tufa. First recorded, 1698; Edward Lhwyd, in a letter ta R. Richardson (Phyt., 2nd ser., I, 268, 1855-56). ' ... growing very plentifully out of a marly incrustation both at Barry Island and Parth Kirig [Porthkerry], in Glamorganshire and out of no other matt-er.' In Wales confined to Glamorgan.

In Great Britain confined to southwwestern England, Wales, West­ morland and the Isle of Man; in Ireland to Co. Meath and the west.

Cosmopolitan. Throughout the Tropical and warm Temperate zones especially in the Northern Hemisphere. Western and southern Europe. Africa. China, Japan. Ceylon. Queensland. Polynesia. D.S.A. (south and west), Guatemala. Colombia southwards to the Amazon region.

Specimens in Herbarium.-Glam.: Barry Island, C.C., c. 1830; Porthkerry, G.F., 1838 and A,KW., 1940; Aberthaw, j,H., 1862; Font-y-gary, H.A.H., 1927; Dunraven Bay. S.R., 1849 and !-I.A,H., 1927.

Subfamily 3. BLECHNOIDEAE Sori formed by fusion of rows of sori (coenosori), short or long, borne on commissures which run parallel to the midrib of the pinna either in a single line or (in one exotic genus) in 1-3 rows on either side; indusium conforming to the sorus . and situated either marginally (and then formed by the incurved and modified leaf margin) or on the under surface anywhere between the margin and the midrib, .but ftlways on the side of the sorus away from the midrib and opening so as to face the latter.-Terrestrial ferns sometimes approaching the tree habit, with erect stock or creeping rhizome (often with runners) and ,imply pinnatifid to bipinnate leathery leaves.-5 genera with about 205 species. .

The Blechnoid Ferns presumably originated like the pteridoideae from ancestors having rows of distinct sori, The only Welsh species, Hard Fern (Blechnum Spicant) , belongs to the sub-genus Eu­ Blechnum, which is characterized by having linear coenosori (with in­ dusium) close to the midrib (cf. Fig. 31). In the sub-genus Lomaria the fertile pinnae are very narrow and the indusium is formed by the margin, Bower suppose:; that the fertile frond of Eu-Blechnum has been derived from one like that of Lomaria by the formation beyond the indusium of a flattened outgrowth (the flange) continuing the leafy lamina. 62 BLECHNUM

Genus 10. BLECHNUM L. Sari (coenosori) linear and, as a rule, occnpying practically the entire length of the segments of the fertile fronds, seldom interrupted. Indusium linear. Scales thin-walled (not lat­ ticed).~About 180 species, only one of which occurs in the Northern Temperate regions, viz.

BLECHNUM SPICANT (L.) With. Hard Fern (PI. 3, Fig. 31.) Stock upright or decumbent, usually 4-5 cm. X 6mm., in old plants caespitose, the young parts clothed with dark, tawny-brown, lanceolate, acuminate scales. Fronds tufted,

Fig.31. Hard Fern (Blechnum Spicant). Left: portion of. sterile frond '; right: portion of fertile frond showing two pi'llnae, one with two coenosori intact, the other with parts of the coenosori cut away in order to show the commissures which link up the secondary veins. (About X 3.) of two kinds sterile and fertile, the stalks of both dark to purple-brown, slightly swollen behind and grooved in front, beset at the base with scales like those of the rhizome. Sterile leaves 10-50 X 2-7·Scm., lying spread out on the ground, winter-green; stalk t-t as long as blade. Blade lanceolate, leathery in texture, glabrous, dark green, shiny above, paler and dull below, pinnate; pinnae 30-60 on either side, set close like the teeth of a comb, linear-oblong with a slight curve towards the apex of the frond, obtuse or acute (sometimes mucronate), entire-margined or slightly crenate, decreasing in size toward the apex and especially toward the base, the lowest segments becoming small and rounded and often separated from one another; rachis deeply furrowed on the A. CAPILLUS-VENERIS 61

Very local in sheltered places on sea cliffs. usually on calcareous tufa. First recorded. 1698; Edward Lhwyd. in a letter to R. Richardson (Phyt .• 2nd ser.. I, 268, 1855-56). ' ... growing very plentifully out of a marly incrustation both at Barry Island and Parth Kirig [Porthkerry], in Glamorganshire and out of no other matt-er.' In Wales confined to Glamorgan.

In Great Britain confined to south-western England, Wales, West­ morland and the Isle of Man; in Ireland to Co, Meath and the west.

Cosmopolitan. Throughout the Tropical and warm Temperate zones especially in the Northern Hemisphere. Western and southern Europe. Africa. China. ] apan. Ceylon. Queensland. Polynesia. U .S.A. (south and west). Guatemala. Colombia southwards to the Amazon region.

Specimens in Herbarium.-Glam.: Barry Island, C.c., c. 1830; Porthkerry, G.F., 1838 and A.E.W., 1940; Aberthaw, J.H., 1862; Font-y-gary, H.A.H., 1927; Dunraven Bay, S.R., 1849 and H.A.H., 1927.

Subfamily 3. BLECHNOIDEAfi. Sori formed by fusion of rows of sori (coenosori), short or long, borne on commissures which run parallel to the midrib of the pinna either in a single line or (in one exotic genus) in 1-3 rows on either side; indusium conforming to the sorns . and situated either marginally (and then formed by the incurved and modified leaf margin) or on the under surface anywhere between the margin and the midrib,.but ;!lways on the side of the sorus away from the midrib and opening so as to face the latter.-Terrestrial ferns sometimes approaching the tree habit, with erect stock or creeping rhizome (often with runners) and ;imply pinnatifid to bipinnate leathery leaves.-5 genera with about 205 species.

The Blechnoid Ferns presumably originated like the pteridoideae from ancestors having rows of distinct sari. The only Welsh species, Hard Fern (Blechnum Spicant), belongs to the sub-genus Eu­ Blechnum, which is characterized by having linear coenosori (with in­ dusium) close to the midrib (cf. Fig. 31). In the sub-genus Lomaria the fertile pinnae are very narrow and the indusium is formed by the margin. Bower supposes that the fertile frond of Eu-Blechnum has been derived from one hke that qf Lomaria by the formation beyond the indusium of a flattened outgrowth (the flange) continuing the leafy lamina. 62 BLECHNUM Genus 10. BLECHNUM L. Sori (coenosori) linear and, as a rule, occupying practically the entire length of the segments of the fertile fronds, seldom interrupted. Ind\,sium linear. Scales thin-walled (not lat­ ticed).-About 180 species, only one of which occurs in the Northern Temperate regions) viz.

BLECHNUM SPICANT (L.) With. Hard Fern (PI. 3, Fig. 31.) Stock upright or decumbent, usually 4-5 cm. X 6mm., in old plants caespitose, the young parts clothed with dark, tawny-brown, lanceolate, acuminate scales. Fronds tufted,

Fig. 31. Hard Fern (Blechnum Spicant). Left: portion of. sterile frond '; right: portion of fertile frond showing two pi'nnae, one with two coenosori intact, the other with parts of the coenosori cut away in order to show the commissures which link up the secondary veins. (About X 3.) of two kinds sterile and fertile, the stalks of both dark to purple-brown, slightly swollen behind and grooved in front, beset at the base with scales like those of the rhizome. Sterile leaves 10-50 x 2-7·5cm., lying spread out on the ground, winter-green; stalk t-t as long as blade. Blade lanceolate, leathery in texture, glabrous, dark green, shiny above, paler and dull below, pinnate; pinnae 30-60 on either side, set close like the teeth of a comb, linear-oblong with a slight curve towards the apex of the frond, obtuse or acute (sometimes mucronate), entire-margined or slightly crenate, decreasing in size toward the apex and especially toward the base, the lowest segments becoming small and rounded and often separated from one another; rachis deeply furrowed on the 'Plate 3, HARD FERN (Blechnum spicant) RhizolTlC with two sterilo fronds and ono i'ertilo frond; the sterile fronds havo been raised into aD ullright position for the purpose of making thf; illustration and the rClll:tining fronds l1ave been removed, Reproduced from M,oore's Ferns of Great Britain and Ireland (Nature- printed by Henry Dradbury), Flatc XLIII, C I Plate 4. Above: HART'S-TONGUE FERN (Phytlit'is scolopendrium) growi.ng in Cl damp and shady situation on old limestone ·walling in a wood Below: RUSTY-BACK FERN (Ceterach (~fficinarum) growing in a dry amI sunny situation on a ll10l"tan'd lin18stone wall B. SPICANT 63 upper side and darker in colour in its lower half. Fertile leaves taller, 15-75 X 2-5cm., placed in the middle of the tuft of leaves and marking the end of the year's growth, stiffiy.erect, not persisting over the winter; stalk up to about 1 as long as blade. Blade linear-lanceolate in outline, pinnate; pinnae linear, suddenly narrowing from a broad base, acute, the highest more and more closely set, the lowest increasingly' shorter and roundish, wider apart and without sori; rachis almost to the apex dark like the stalk. Venation Eupteridian to almost N europteridian; the secondaries (in the fertile leaves only) joined by a commissure running below the receptacle. Sori linear, situated midway between the leaf margin and the midrib and parallel with the latter, running almost the entire length of the pinna. Indusium whitish at first becoming brown, swollen and somewhat blistered in appearance. Common on acidic soils in woods, heaths and hedge-banks and on rock ledges. First recorded, 1800; Bingley,* Tour round North Wales, 2, 430. 'Moist heaths between Caernarvon and Llanberis.' Recorded from every county in Wales. Throughout the British Isles. Circumpolar but discontinuous. Throughout Europe from Iceland and Norwegian Lapland t9 Spain and the Mediterranean region. Asia Minor. Caucasus. Madeira. North~eastern Asia from Kamtschatka to Japan. Western North America from Alaska to California.

Subfamily 4. ASPL£NIOID£A£· Sori superficial, usually oblong to linear, more or less inclined to the midrib, borne either on one or on both sides of the fertile vein; indusium usually present, membranous, either single, oval to linear, opening inwards or outwards, or double with the two parts placed back to back on the same vein and free, or (in Athyrium) fused at the upper end; sporangia small with thin stalks.-Mostly terrestrial ferus, with erect stock or creeping or climbing rhizome clothed with scales; leaves of very diverse habit, often more or less clothed with scales, rarely with hairs.

* 2 vols. London, 1800. A catalogue of the more uncororoo~ vVelsh plants is appended. 64 PHYLLITIS

The Asplenioid ferns show resemblances both to the Blechnoid ferns and to the Dryopteroid ferns. Thus the Spleenworts (Asplenium) with their linear sori may have been derived from ferns like the Buckler Ferns (Dryopteris) with reniform sori: Athyrium illustrates possible connecting links, its sari being all shapes from reniform to oblong. Rustyback Fern (eeterack) resembles the Spleenworts in all essentials except that it has almost lost its indusium.-The Hart's-tongue Ferns (Phyllitis) resemble the Spleenworts in the shape of their sori, in the peculiar X-shaped skeletal strands of the leaf stalk and in the latticed scales. Bower, unlike Christensen, linked up this genus with the Blechnoideae supposing the resemblances referred to to be due to con­ vergent evolution. However, since the publication of his Filicales, a further argument in favour of a close relationship between Phyllitis and Asplenium has beel1 supplied by the discovery that Hart's-tongue Fern has formed several hybrids with species of Asplenium.*-The rela­ tionships of Cystopteris again are not clear: it might well be classified with Dryopteris.

Tribe I. ASPLENIEAE Sporangia inserted directly on the veins, usually on one side only; indusium usually single, straight. Rhizome scales firm, latticed.

Genus 11. PHYLLlTIS Hill Sari in twin pairs, those of two neighbouring veins parallel and close'l ultimately appearing as one. Indusia linear, each attached on one side of the receptacle, those of a pair opening towards each other. Leaves tufted, simple or slightly lobed, the veins free (except in two American subgenera}.-About 8 species.

PHYLLlTIS SCOLOPENDRIUM (L.) Newm. (Scolopendrium vulgare Smith) Hart's-tongue Fern (PI. 4, Fig. 32.) Stock up to 6 x O·5cm., ascending to almost erect, the brown surface of the younger parts very thickly clothed with brown (tinged with violet), linear-lanceolate to lanceolate, acuminate scales, having heart-shaped bases. Fronds I0-60cm., tufted, strongly curved outwards and downwards, winter­ green; stalk very variable in length, up to half as long as the blade, usually less, green to dull brown merging into purple­ brown at the base, practically semicylindrical with a flat or

'" The generic name Aspler.ophyllitis has been proposed for these hybrids. See AIston Proc. Linn. Soc., 1939-40, pt. 2, 132-144 (1940). P. SCOLOPENDRIUM 65 feebly convex upper surface and usually with shallow grooves along the flanks, the swollen base clothed with scales like those of the rhizome, the upper part of the stalk with gradually smaller and narrower scales, becoming more or less glabrous when old. Blade 5-40 X 1-6cm., clear green, fleshy or leathery in texture, more or less strap-shaped (lanceolate, linear-lanceolate or oblong­ lanceolate). cordate at the base and often narrowed slightly to a little bay just above, narrowed toward the apex, obtuse or su b-acu te, the margin more or less wavy; midrib stout, beset, when young at least, with scattered subulate or hair-like scales; venation Taeniopteridian, with the vein-endings swollen. Sori linear, usually more abundant in the upper part of the frond, in vigorous plants occupying almost the whole width from midrib to margin, but usually less, the sporangia of a pair of sori running together to form a dense brown cigar-shaped mass. Indusium membranous, its margin en­ Fig. 32. Hart's-tongue Fern (Phyllitis 5colo­ tire, at first colourless, finally brown pendrium). Portion and reflexed. of blade (about natural size) to show A large number of varieties of Hart's­ Taeniopteridian vena­ tongue Fern (many of them having the tion and twinned sari. • leaf-blade curled and cleft into lobes and segments) ocCUr wild and many more have arisen under cultivation. No doubt most of these should be regarded as monstrosities,. but some even of the most monstrous breed true. Woods, hedge-banks, walls, and rock ledges; common on limestone, less so elsewhere. First recorded ante 1597 by William Salesbury in his manu­ script herbal. 'yn eymyl tal acre [Talacre, Flints.].'

Recorded from every county in Wales.

Throughout the British Isles.

Circumpolar. Throughout Europe. North Africa. Azores. Madeira. Asia Minor to Persia. Japan. Eastern North America from New Brunswick and Ontario southwards to Tennessee. 66 ASPLENIUM

Genus 12. ASPLENIUM L. Spleenworts Sori usually oval to linear and single, sometimes hooked at the end (cf. Atkyrium) or double back to back (as they are typically in the foreign genus Diplazium).· Indnsinm con­ forming to the shape of the sorus, usually opening inwards, i.e. toward the midrib but occasion­ ally outwards, i.e. toward the Fig, 33. Single linear sorns margin. of Wall-rue (Asplenium Ruta-muraria), Terrestrial or epiphytic ferns of very diverse habit. Fronds usually pinnate though sometimes simple, herbaceous or firm in texture. Scales latticed (as also in Phyllitis and Ceterack) sometimes with a 2-3-layered dark stripe down the middle. Venation free in all European species.-A large genus of about 650 species.

KEY TO SPECIES

A Segments with, a distinct midrib; veins simple or once forked; sori oblong or linear B Blade simply pinnate C Rachis winged 1. A. MARINUM CC R~chis not obviously winged D Rachis black throughout 2. A. TRICHOMANES DD Rachis green above .. .3. A. VIRIDE BB Blade bi- or td-pinnate E Blade lanceolate in outline, nar­ rowed at the base; sari oblong 4. A. OBOVATUM EE Blade triangUlar in ou tUne, widest at the base; sori linear 5. A. ADIANTUM~NIGRUM AA Segmel,lts without a distinct midrib ; veins repeatedly forked and arranged fan~wise; sori linear F Blade pinnate or bipinnate G Pinnules more or less obovate, rounded at the apex 6. A, RUTA-MURARIA GG Pinnules lanceolate, obtuse 7. X A. BREYNII FF Blade forked 8. A. SEPTENTRIONALE

* See below under A. Adiantum~nigrum (p. 72). Plate 5. \VELSI-I SPLEENWORTS Above: AsPlenium viride and A. tricllOl!1anes Dolo·w: A. adirtnlwJ1l-nigrum, A. ouovattfm and A. mari-num (For remaining three species see text figtIres) Plate G. Left: BRITTJ~E BLADDER FERN (Cystopteris fragilis) lVIic1clle: LADY l~ERN (.11 thyrium fili."C-femina) Right: RIGID BUCKLER FERN (Dryopteris villarsii) A. MARINUM 67

I. ASPLENIUM MARINUM L. Sea Spleenwort (PI. 5, Fig. 34.)

Stock caespitose, erect to .decumbent, densely clothed with purplish- to brownish-black, linear-lanceolate scales. Fronds tufted 8-50cm. ; stalks about t-! as long as blade, reddish to purplish-brown with a few scales at the base, otherwise glab­ rous, smooth and shining. Blade 4-40cm., narrowly to broadly lanceolate, somewhat leathery in texture, pinnate; pinnae bright green, oblong to broadly ovate, very unequal at the base (broadly truncate and often almost lobed on the side towards the frond apex, cuneate on the other), and rounded Df rarely sub-acute at the apex, the margin broadly crenate, the upper pinnae running together; venation Eupteridian, the low­ est secondary twice or thrice forked, the remainder usually Fig. 34. Sea Spleenwort (Asplenium once only, all veins marinum). Median pinna of a well­ ending considerably developed frond, twice natural size. inside the margin; rachis flanked by wings formed by the decurrent bases of successive pinae. Sori linear, 'situated on the acroscopic forks of the secondary veins. Indusium also linear, opening inwards. Clefts of sea-cliffs, locally frequent or common; less frequently on walls near the coast. First recorded, 1639; Johnson, Mere. Bot., pars alt., 9, 1641. Llanddwyn, Anglesey. Distribution in Wales: Glam., Carm., Pemb., Card., Mer." Caern., Denb., Angl.

All round the coasts of the British Isles, except the Shetlands and east England (south Yorkshire to Sussex).

Atla~tic coasts of Europe from the Orkneys to Spain. Western islands of the Mediterranean. North Africa. Atlantic islands. 68 ASPLENIUM

Specimens in Herbarium.-Glam.: Gower, J ,W,G.G., 1840; Mumbles. C.R.B., 1848; Warren Hill, Briton Ferry, C.H.B., 1850; or. Caswell Bay, C.R.W., 1908; Bacon Hole and Culver Hole, Cower, l.A.W., 1923; Dunraven Bay, H.A.H., 1927; Mewslacle Eay, H.A.H., 1933, Carm.: Pendine, H.H.K., 1907. Pemb.: between Musselwick and Newgale, R.; Tenby, J.H.A.S., 1884: nr. St. David's, M.B" 1923; Skomer Island, H.A.H .. 1927, Card.: nr. Aberystwyth, J.H.S .• 1922; nr. Tresaith, W.R.R., 1937. Mer.: Harlech Castle, D.A.].. 1898. Caern.: Gt. Ormc's Head, C.W., 1876 and H.W., 1861. Denb.: Llan­ galleo, H.S.) 1879. Angl.: Holyhead, lE.G., 1879 and W.!., 1895;' Rhosneigr, M.H., 1928. .

2. ASPLENIUM TRICHOMANES L. em. Huds. Maidenhair Spleenwort (PI. 5, Fig. 35.) Stock up to 5 X 0·2cm., creeping or decumbent, densely caespitose, the younger parts clothed with dark brown, linear­ lanceolate, acuminate scales, usually with a black centni.l stripe. Fronds 5~35cm., tufted, winter-green; stalk i~t as long as the blade, wiry, brownish to purplish-black, rounded behind and flat in front with a very narrow pale brown (at first greenish) membranous, brittle, winged border on either angle, glabrous and shiny. Blade 4~30 X 0·5~2cm., linear in out­ line, pinnate; pinnae up to about 30 or even 40 pairs, dark green, thick, glabrous, roundish oblong (except the lowest which are Fig. 35. Maidenhair usually broadly ovate and also Spleenwort (Asplenium Trichomanes). Median smaller), unequal at the base pinna from a large~ (truncate on the side toward the leaved form showing apex of the frond, cuneate on the the sori on the acros­ other), rounded at the apex, cren­ copie branches of the secondary veins. ( X ate along the margin except on 4.) the side away from the frond-apex, becoming detached from the rachis during the second season leaving behind a small brown tooth-like projection; venation Eupteridian, the secondaries fo~ked, their branches running into the crenations but ending short of the margin; rachis brownish to purplish black, winged, eventually becoming bare of pinnae. Sori linear, situated midway between the margin and the midrib, on the acroscopic branches of the secondary veins or in part on the secondaries themselves. Indusinm also linear, entire or slightly crenate, opening inwards. A. TRICHOMANES 69

Common on old walls and in rock crevices; more rarely on hedgebanks. First recorded ante )597 by WiUiam Salesbury in his manu- script herbal. 'ar y bont vaen ar Lugwy [Bettws-y-coedJ.' Recorded from every county in Wales. Throughout Great Britain. Cosmopolitan. In the Temperate and Sub-Arctic zones of both hemispheres and in the high mountains of the Tropics. Europe. North Africa. North Atlantic islands. Western Asia. Hitnalaya. China. Japan. Australia. Tasmania. New Zealand. Hawaiian islands, Cape 01 Good Hope. Madagascar. Throughout North America (except the extreme north) and south to Peru.

3. ASPLENIUM VIRIDE Huds. Green Spleenwort (PI. 5, Fig. 36.) Stock up to 10 X 0·25 i'm., decumbent or ascending, caespit­ ose, the younger parts clothed with dark brown, linear­ lanceolate, acuminate scales, usually without a central stripe. Fronds 4--20 cm., tufted, not usually winter-green; stalks l-t as long as the blade, reddish-brown to dark purplish-brown at the base only, green higher up, with a few . scattered hair-like scales, becoming glab­ rous, approximately semicircular in sec­ tion, not winged. Blade 3-15 X O·S-)·Scm., linear in outline, pinnate; pinnae up to about 30 pairs, bright green, delicate, glabrous, ovate (the lowest broadly ovate), somewhat unequal and more or less cun­ eate at the base, obtuse at the apex, Fig. 36. Green crenate-margined (often deeply so), not Spleenwort (As­ plenium viride). falling from the rachis but dying down Median pinna with the frond as a whole; venation from a well­ Euptericlian, the secondaries forked, their developed plant branches running into the' crenations but showing the sari on the second­ ending short of the margin; rachis ary veins (X 3). green, slightly grooved on the upper side, with a few hair-like scales in the lower part when young. Sori linear, situated toward the midrib and at a distance from the margin, on the secondary veins and extending up their acroscopic forks. Indusium also linear, entire or slightly toothed. 70 ASPLENIUM

Locally frequent in crevices of shady rocks (especially limestone in mountainous districts). First recorded, 1695; Lhwyd in Camden's Britannia (ed. Edmund Gibson), 702. 'Snowdon.' Distribution in Wales: Mon., Glam., Brec., Carm., Mer.. Caern., Denb. . North and south Wales, the north of England, Scotland, and Ireland (south-west and north-west). Circumpolar. Europe, from the Arctic to the southern Alps. Caucasia. Siberia. Western Asia to Himalaya. ~orth America. ~ew­ foundland. ='few Brunswick to Alaska, southwards to Vermont, Wyoming and Oregon. Specimens in Herbarium.-Mon.: Lasgarn, T.H;T., 1869; Taren yr Esgob, S.G.C., 1941. GJam.: l\lorlais Castle Hill, A.KW., 1923. Brec,: Cefn Cil-Sanws, G.R.W., 1908; between Maen Madoc and Ystradfelltc, H.A.H., 1925; Brecon Beacons, A.E.W., 1926; Cribarth, Pcn-y.,cae, A.E.W., 1927; Craig y CHau, H.A.H. and A.E.W., 1927 ;. Craig Cerig-gleisiad, H.A.H'J 1927, 1931; Dyffl'yn Crawnol1, A.E.W., 1929; Cwm Pwll-y-Rhyd, A.E.W., 1934. Carm.: Carmarthenshire Fan, H.J.H.., 1902; above Pont Clydach, H.H.K., 1907; Careg-ogof Mountain, J.F.]., 1931. Mer.: Cader Idris, A.W., 1931. Caern.: Snowdon, C.C.B., 1830; above Llyn Idwal, C.W., 1876; Cwm Glas, H.A.H., 1924; between Cv·,:m Clyd and Y Garn, C.M.L., 1926; CWlll Idwai, ].E.Y., 1881.

4. ASPLENIUM OBOVATUM Vivo (A. lanceolatum Huds.) Lanceolate Spleenwort (PI. 5, Fig. 37.) Stock short, 1·5-3 X about 0·5cm., erect to decumbent, caespitose, densely clothed with brownish-black, shining, subu­ late scales, with long hair-like points. Fronds 10-30(40)cm., tufted; stalks i-i as long as the blade, dark reddish- to purplish­ brown (the colour extending upwards on the under side), semi­ circular in section, with a few subulate or hair­ like scales especially at the base, otherwise glabrous. Blade 6-20 (30) Fig. 37. Lanceolate Spleenwort (AsP­ lenium obovatum) , Median pinna from X 3-7(10)cm., lanceo­ an average-sized frond (x 2). late in outline (slightlY A. OBOVATUM 71

narrowed at the base), rigid, bip,nnate; pinnae. up to about 18 or 20 on either side (the lowest wide apart), lanceolate,. ovate-lanceolate or ovate, very shortly stalked, pinnate, be­ coming pinnatiftd and ultimately simple toward the apex of the frond; pinnules obliquely ovate, coarsely toothed with mucronate teeth, the lower ones cuneate at the base, the upper ones running together, the basal acroscopic pinnule usually larger than the rest and frequently lobed or even pinnatifid ; venation Pecopteridian, the lower tertiaries usually forked, the upper ones undivided, the ultimate venules running into the pinnule-teeth but ending short of their apices; rachis usually reddish' to purplish-brown on the under side except toward the apex, often with scattered jointed hair-like scales, which occur on the rachises of the pbnules also. Sori shortly oblong, situated nearer to the margin of the pinnule than to the midrib, the sporangia sometimes almost covering the whole frond beneath. Indusium oblong, entire, opening inwards. Rare (or in a few places frequent), in rock crevices and on old walls, the sides of wells and those of old mine shafts. First recorded, 1840; Newman, Hist. Brit. Ferns and Allied Plants, ed. 1. 'Merionethshire, near Barmouth ... Caernar­ vonshire, ... between Tan-y-bwlch and Aberglaslyn.' Distribution in Wales: Glam., Brce" Carm., Pemb., Mer., Caern., [Denb. ?J. Chiefly near the sea: Wales, England (south~west, south~east, Cumberland and south~west Yorkshire) and the south of Ireland. Coasts of western Europe from the north of England to the Mediter~ ranean region, with small outHers in Alsace-Lorraine and Germany. Algeria. Atlantic islands. St. Helena. Specimens in Herbarium.-Glam.: Pontypridd, T.H.T., 1894. Carm.: Pendine, H.H.K., 1907. Mer.: nr. Barmouth, C.W., 1877, Caern.: Penmaen Bach, vV.H,R, 1861; Portmadoc, G,H.B., 1917 and J .E.G., 1891; nr. Abersoch, ] ,E.G., 1890; Portmadoc, ] .H.S., 1925,

ASPLENIUM FONTANUM (L.) Bernh. Smooth Rock Spleenwort An essentially mountain species in southern France and Central Europe. As a rule much smaller than A. obovatum, from which it differs also in its entirely green rachis, much reduced .lower pinnae, obovate, cuneate-based pinnules and mucronate teeth. Not a native of Britain. The specimen labelled 'A. jontanum' from 'betwixt Tan-y-bwlch and Tremaddoch' in Dr. J. Power's herbarium* is not this species but probably an immature state of Athyrium Pilix­ fell/ilia.

* We are indebted to the Holmesdale Natural History Club, Reigate, for the loan of this specimen from their museum, F 72 ASPLENIUM

5. ASPLENIUM ADIANTUM-NIGRUM L. Black Spleenwort (PI. 5, Fig. 38.) Rhizome 10 x Q·Scm., creeping or decumbent, branched or caespitose, the younger parts clothed with brownish-black, subulate scales with long hair-like points. Fronds 1O-45cm., tufted,. winter-green; stalk about as long as blade, thickened and scaly at the base, dark purplish-brown. Blade 5-25 X 2·5-16cm., very variable in outline, ovate, ovate-lanceolate or narrowly triangular but always widest at the base, often Some­ what acuminate, firm in texture, dark shining green above, paler beneath, when young with scattered minute brownish­ black hair-like scales, bi-or tri- or even almost quadri-pinnate at the base, becoming less divided toward the apex and

Fig. ~8. Black SpleCllwort (Asplenium Adiantum-nigrurn). Median pinna from an average-sized frond (X 2). ultimately only pinnatifid; pinnae up to IS on either side, alternate' or sub-opposite, pinnate Or bipinnate, rarely almost tripinnate at the base of the basal pinnae, the lowest pair larger than the succeeding. the lower and middle ones sta.lked, the upper ones becoming sessile, their rachises winged through­ out; pinnules alternate, the basal ones of the lower and middle pinnae pinnate or pinnatifid, those on the side of the pinna toward the apex larger than the others; ultimate segments ovate to lanceolate, acute or rounded at the apex, more or less toothed in the upper half, cuneate at the base; venation Sphenopteridian without a conspicuous midrib, the vein endings running out into the teeth but not reaching the points; maiu rachis purplish-brown on the lower half of the under A. ADIANTUM-NIGRUM 73 surface, otherwise green. Sori linear situated toward the middle of the segment, on the sec'ondaries or their acroscopic branches, the lowest ones sometimes paired back to back or occasiollally hooked as in Athyrium; the mass of sporangia finally occupying the whole of the middle of the segment. Indusium conforming in shape to sorus, usually opening inwards, entire. Common in rock crevices and on walls and hedgebanks. First recorded, 1726; Littleton Brown in a letter to Dillenius. (Druce and Vines, The Dillenian Herbaria, lxxiii, 1907.) Tenby. Recorded from every county in Wales.

Throughout the British Isles. Cosmopolitan. .Europe, extending northwards to the Faeroes and Southern Scandinavia. North Africa and the Atlantic islands. Western Asia. Northern Asia to Himalaya. Hawaiian Islands. St. Helena. The highlands of East and West Africa, and South Africa. IVIascarene Islands. * * See footnote to p. 45.

6. ASPLENIUM RUTA-MURARIA L. Wall-rue (Figs. 33, 39.) Stock short, creeping, branched, the younger parts clothed with blackish-brown subulate scales with hair-like points. Fronds 2-12(15)cm., tufted, winter-green; stalks as long or twice as long as the blade, dark purplish-brown at the base only, beset when young with numerous minute, globose, deciduous glands and a few hair-like scales. Blade 1-6 X 1-4'5cm" triangular-ovate or ovate-lanceolate in outline, leathery in texture, bipinnate or almost tripinnate at the base; pinnae 4 or 5 on either side alternate or the basal ones sub­ opposite, widely spaced, variable in their degree of subdivision, the lowest two pinnae in robust plants pinnate with the basal pinnules trifid, the third and fourth pinnae pinnate or ternate, the rest less and less divided towards the apex of.the frond, the terminal one being entire or slightly lobed; ultimate segments very variable, obovate, oblanceolate or rhomboidal, cuneate at the base, obtuse or rounded at the apex, serrate or crenate in the 74 ASPLENIUM upper half; venation Sphenopteridian to almost Cyclopter­ idian, the midrib not clearly distinct, the veins once to several times forked. Sorl linear borne on the veins, 1-3 on either side of the middle line, occasionally paired back to back, the sporangia ultimately covering the under surface. Indusium similar in shape to the sorus, finely crenate, usually opening inwards.

Common on rocks and walls, especially limestone (including mortar). First recorded, 1695; Lhwyd in Camden's Britannia (ed. Edmund Gibson), 699. 'On Snowdon hill.'

Recorded from every county in Wales.

Throughout the British Isles.

Circumpolar. Throughout Europe. Algeria. Western and northern Asia southwards to Afghanistan and the Fig. 39. Wall Rue (Asplen­ eastern Himalaya. Eastern North ium Ruta-muraria). Single America: Vermont to southern frond from a plant of aver­ Ontario and Michigan and, south via age development, natural Missouri to Alabama. size. On the left: a por­ tion of the frond bearing an ultimate segment mag­ nified (X, 3) to show the venation and the sori with Var. PSEUDOGERMANICUM Heufl. * their crenate-edged indusia. Frond up to IOcm. ; blade tri­ angular or ovate-triangular in outline, lax, bi- or rarely tri­ pinnate; lower pinnae ternate or trifid, the upper entire or slightly-lobed at the apex; pin­ nules (or simple pinnae) up to 12 X 3mm., narrow rhomboid or wedge-shaped, toothed or crenate at the apex. In Wales recorded from Caeruarvonshire and Anglesey.

'" The Welsh plant which has gone under this name may prove to be a hybrid between A. Ruta-muraria and A. septentrionale,' cf. p. 137 of Alston's paper as above (page 64, footnote). A. BREYNII 75

7. X ASPLENIUM BREYNII Retz. (A. germanicum auct. non Weiss. A. septentrionale X Tricltomanes) Alternate-leaved Spleenwort (Fig. 40.)

Fig. 40. Alternate~leaved Spleenwort (XAsptenium Breynii). Single frond (natural size). On the left: a median pinna magnified (X 3) to show venation and sari. Stock short, creeping to ascending, caespitose, the younger parts thickly clothed with blackish-brown to, black subulate scales having no central stripe. Fronds densely tufted, 2·5-17cm., winter-green; stalk about as long as the blade 76 ASPLENIUM

or longer, channelled above (as is the rachis) up to the middle, shining chestnut- to blackish-brown (less often brown up to and including the rachis, but beneath only), Blade 1 ,5-7·5 X O·8-2·8cm., linear-lanceolate in outline, fairly thick and herbaceous in texture, pinnate (at the base bipinnate; pinnae alternate to sub-opposite, set widely apart, the lowest trifid or ternate (with the lowest (acroscopic) pinnule only mote or less distinctly stalked), the middle pinnae unequally lobed (the lowest (acroscopic) lobe the largest), the upper pinnae undivided and incurved toward the rachis and the terminal one pinnatifid; ultimate segments lanceolate or oblanceolate, cuneate at the base, deeply and irregularly toothed toward the apex; venation· Sphenop­ teridian, without a distinct midrib, the vein endings running to the teeth. Sari linear, at most 2-4 ih two rows on each segment, occasionally paired back to back, the sporangia when ripe covering the middle part of the segment. Indusium also linear, its margin entire or at most slightly waved, usually opening inwards. On rocks, very rare. First recorded, 1848; Moore, Handb. Brit. Ferns, ed. I, 117. 'Wales.' Distribution in Wales: Brec.~ Mer., Caern.

Very ,rare in Wales, Somerset, north of England and sQuth7east . Scotland. Absent from Ireland. Mountainous districts of Europe from Norway to the southern Alps. Kashmir and Hong Kong. Specimens in Herbarium.-Mer.: Dolgelley, C.W.; Llyn Cae, Cader Idris, J.,E.G,; nr. Tyn~y-groes, ].H.S., 1928. Caern.: nr. Penmaen~ mawr and nr. Llanrwst, H,W., 1861; Gelli CemlYll, ] ,E,G.

8. ASPLENIUM SEPTENTRIONALE (L.) Hoffm. Forked Spleenwort (Fig. 41.) Rhizome creeping, branched, the younger parts densely clothed with brownish-black subulate scales with hair-like points and ciliate margins. Fronds 5-15cm., tufted; stalk as long up to several times as long as the blade, dark shining chestnut- to blackish-brown at the base only and with scat­ tered very minute brownish hairs. Blade stiff and leathery in texture, irregularly forked to pinnate or bipinnate; pinnae only one or two in addition to the terminal one, the lowest A. SEPTENTRIONALE 77 pinna (and less often also the next) sometimes divided into a larger terminal pinnule and a smaller lateral one standing on the side towarlj the frond apex; pinnae and plnnules 5 in all at the most linear-lanceolate. acute or acuminate at the apex, with a /ew long irregular subu­ late teeth in the upper half, sometimes narrowly cuneate at the base, the lower ones only stalked; venation Spheno­ pteridian, without a distinct midrib. Sori linear, 1-5 on each segment, one above the other or more or less parallel, practically covering the whole under surface. Indusium also lin,ear, eritire, opening inwards. Crevices of rocks and walls (not limestone) .. First recorded, 1695 ; Lhwyd in Camden's Britannia (ed. Edmund Gibson), 700. 'On I "",1 top of Carnedh Llewellyn,' , near Llyn Lhechyd [Caern.].' \ Distribution in Wales: Card., Mont., Mer., Caern., [Denb. I]. Rare in north Wales, England and Scotland. Absent from Ireland. Circumpolar. Europe, generally in the mountains, from Norway to the Mediterranean region and the Caucasus. Northern Asia to the Himalaya and the Altai Mountains. Western U.S.A. Specimens in Herbarium.-Mer.: Fig.41. Forked Spleenwort nr. Dolgelley, c.-W, ; Croesor, (Asplenium septentrionale). H.H.K., 1909; nr. Tyn-y-groes, Single frond (natural size). On ] ,H.~., 1927, Caern.: Llyn-y-cwm, the right a single pinna mag­ W.W., 1835; nr. Llanwrst, H.W., nified (X 3) to show venation 1861; Moel-yr-ogof, ] .E.G., 1893. aIJ-d sari.

Genus 13. CETERACH Garsault Sori oblong to linear, situated on the inner side of the secondary nerves or of their acroscopic forks, with rudimen­ tary, very narrow indistinct indusia or none. 78 CETERACH Small xerophilous ferns having short more or less upright stocks beset with latticed scales, and tufted pinnatifid fronds clothed beneath also with large latticed scales; veins of the leaf segments pinnate and forked, anastomosing near the margin.-5 species, Old World only.

CETERACH OFFICINARUM Lam. & DC. Rusty-back Fern (PI. 4, Fig. 42.) Stock short, upright or ascending, often caespitose, clothed with blackish-brown to blackish, lanceolate, acuminate scales. Fronds 3-20cm., tufted, winter-green; stalk short, t-! as long as the blade, at the base dark brown or blackish with scales similar to those of the stock, higher up with the same kind of scales intermixed with scales similar to those on the blade and with others intermediate between the two. Blade 2·5- 17 x O·5-3cm., thick and leathery, linear­ lanceolate in outline, deeply pinnatifid, deep Fig. 42. Rusty-back Fern (Ceterack officinarum). Part of the upper or yellowish green and third of a frond (X 3) showing two with a few scattered segments, the lower one clothed with scales especially on the overlapping scales, the upper one midrib above, densely with the scales removed, revealing the reticulate venation and the sori clothed below with in their relation thereto. tawny (at first silvery) o vat e- ac U ill ina te • .apparently peJtate scales, which are attached near their bases, set so as to overlap like tiles on a roof, and project beyond the margin; segments alternate, ovate or oblong, rounded at the apex, entire or crenate along the margin, decurrent at the base, the lowest much smaller and sometimes completely separated; venation Neuropteridian, the second­ aries forked and forming one (or sometimes in part two) rows

,of anastomoses, the ultimate venules free. Sori linearj .situated about midway between the midrib of the segment and the margin. Indusium rudimentary or absent. C. OFFICINARUM 79 On old (lime-mortared) walls and limestone rocks; common or frequent in south Wales, rare in north Wales. First recorded, 1696; Edward Lhwyd in a letter to Dr. R. Richardson. (Phyt., 2nd ser., I, 268, 1855-6.) 'In South Wales.' Recorded from every county in Wales. Great Britain chiefly in the south and west, northwards to east Perthshire. Throughout Ireland. Throughout the Mediterranean region extending into Central Europe and along the Atlantic coast to Belgium and Great Britain. Caucasus. North Africa. Western Asia to north~western Himalaya. " Madeira. Specimens in Herbarium.-Mon.: Wyndcliff, C.B., 1873; Tredegar Park, A.E.W., 1923; Skenfrith. S.G.C., 1935; Cwmcarvan, S.G.C., 1936; Llanthony Abbey, S.G.C., 1940; The Blorenge, S.G.C., 1941. Glam.: Mumbles, C,R.B., 1848; l\ierthyr Tydfil, G.R.W., 1907; Llandough, nr. Cardiff, A.E.W., 1920. Brec.: Talgarth, 1834 (Herb. Horwood); Craig y Cilau, H.A.H, and A.E.W., 1926. Had.: Rhayadr, Comm. R.L.S., 1922. Carm.: Llandovery, H.H.K., 1907; Llanegwad, C,W.B., 1926; nr. Ferryside, A.E,W., 1930; Llangadock, ].F.]., 1931. Pemb.: Tenby, J.G., 1924. Card.: Llechryd, J.A.Whe., 1941. Mont.: Machynlleth, P.G.M,R., 1929; Pool Quay and Derwenlas, J.A.W., 1940. Mer.: Harlech, A.W., 1931; Abertafol, J,A.W., 1939. Caern.: nr. Vaynol, C.W., 1876 and J .E.G., 1878; Rhyd Llanfair, nr. Bettws y Coed, J .R.H., 1944. Var. CRENATUM Moore Margins of the lobes distinctly crenate-sinuate; usually larger than the common form. Recorded from Glam., Brec., Carm., Caern., Angl. SpeCimens 1Il Herbarium -Glam.: Cefn On, P.W.R. Brec.: Penderyn, A.E.W., 1923 Caern.: Bangor, A.We., 1884. Angl.: Llan­ ddona, F.T.J .• 1942. Tribe 2. ATHYRIEAE Sporangia borne on receptacles with a vascular strand branched off from the vein; indusium variable. Rhizome scales usually iarge, thin walled. Genus 14. ATHYRIUM Roth Sori variously shaped from round to linear, the indusia in typical species hooked (Le. consisting of two unequal arms placed back to back, the louger arm opening inwards and joined at the outer end to the shorter arm which opens out­ wards), in other species horse-shoe-shaped or kidney-shaped (cf. Dryopteris) or straight (cf. Asplenium). Terrestrial, usually erect ferns with somewhat limp, soft textured pinnate to tripinnate leaves, with free veins, without hairs but with some scales.-About 180 species, mostly eastern Asiatic, few in the tropics. 80 ATHYRIUM

ATHYRIUM FILlX-FEMINA (L.) Roth Lady Fern (PI. 6, Fig. 43.) Stock rather stout, up to 10 X O·Scm., erect or ascending, simple or sometimes branched, beset with the bases of old fronds, the younger parts clothed with dark brown or some­ times blackish, lanceolate or ovate-lanceolate scales. Fronds 20-90cm., erect or gracefully spreading or drooping; stalk 1-1 as long as the blade, its base purplish black, swollen and broad­ ened, tapering above and below and beset with brownish, lanceolate scales, the upper part pale green to dull purp­ lish-red with fewer scales. Blade 15-70 X 5-2Scm., lanceolate in outline, bi­ or tri-pinnate, usually rather flaccid and thin in texture, bright clear or yellowish green'; pinnae numerous (up to about 30 on either side) alter­ nating or less often sub-opposite, sessile or shortly stalked, mostly close set (but the lowest wider apart and sometimes bent downwards), linear­ lanceolate or linear-oblong, acumin­ ate; pinnuies alternate (except the lowest), oblong or oblong-lanceolate, often a little curved toward the apex of the pinna, sessile, unequal and more or less decurrent in the direction of the base of the pinna, pinnately lo.bed, the lowest segments pinnately toothed, the upper ones with 2-3 Fig. 43. Lady Fern obtuse or sub-acute teeth or simple; (Athyrium Filix­ venation Pecopteridian, the veins of jemina). Median pin­ the lower pinnule-segments pinnate, nule from fifth pinna on one side of an those of the remainder only forked; average-sized frond rachis with minute hairs or scaltered Ix 5). subulate scales or glabrous. Sori situated on the lowest acroscopic veinlets, forming a single rowan either side near the midrib of the pinnule, in tri­ pinnate leaves two short rows also on the lowest segments of the third order, the lowest sari of each row kidney-shaped, horse-shoe-shaped or more or less hooked, the upper ones A. FILIX-FEMINA 81 nearly or quite straight, and oblong or linear.. Indusium similar in shape to the sorus, attached on one side, more or less inflated, membranous, the free ~argin usually ciliate or irregularly toothed. Common in woods and on hedgebanks and in other damp, shady and sheltered places, and in rocky situations in mount­ ainous districts. First recorded, 1726, Herb. Dillenius. (Druce and Vines, The Dillenian Herbaria, 47, 1907.) 'Anglesey and Landberrys [Llanberis, Caern.].' Recorded from every county in Wales. Throughout the British Isles. Cosmopohtan. Throughout Europe North Africa and the Atlantic islands. Western and northern A~ta extending to northern India, China and Japan. Java, Temperate North America from Newfound­ land to British Columbia, southwards to the Gulf Straits and California. Mexico to Peru, Var. ERECTUM Syme Fronds suberect; stalks rather long (up to t as long as the blade); blade firm, oblong-lanceolate, almost parallel sided, tapering more towards the apex than the base, which is rather abrupt; lowermost pinnae many times longer than broad; pinnules or segments strap-shaped or linear-triangular, often with the edges recurved when growing in exposed places. Recorded from Glamorgan.

Var. WATSONI Syme Fronds suber~ct; stalks about t as long as the blade; blade firm, oblong-lanceolate or ovate-oblong in outline, tapering very little towards the base; the lowermost pinnae as long as or almost as long as the ·succeeding pair; pinnules oblong-lanceolate or ovate, flat. The original specimens (cultivated in H. C. Watson's garden) were believed to have been introduced from south Wales.

Var. CONVEXUM Newm. Fronds suberect; stalk about t as long as the blade; pinnae widely. spaced, pinnate; pinnules narrowly lanceolate, widely spaced, edges recurved, the lowermost pinnules deeply toothed or lobed, the rest becoming less deeply toothed towards the apex, the uppermost being only obscurely toothed. Recorded from Brec., Pemb., Caern., Angl. Specimen in Herbarium.-Pemb~: .ur. Treffgarne Ro~ksJ A,E,W.,' 1939. 82 ATHYRIUM

Var. PRUINOSUM Moore Stalks, rachis and midribs covered with short, white, 1-2-celled club-shaped or pin-headed hairs, which owing to their fragility fall off very easily. Specimen in Herbarium.-Brec.: Clydach, A.E.W., 1925.

Var. INCISUM Newm. Fronds large drooping, broadly lanceolate; pinnae and pinnules widely spaced; pinnules lanceolate, pinnatifid, the lobes toothed. Recorded from Mon., Glam., Brec., Pemb., Caern. Specimens in Herbarium.~Mon.: Barbadoes Hill, W.A.S., 1895. Glam.: nr. Radyr, H.} .R., 1909. Brac.: Cellwen, A.L., 1899.

ATHYRIUM ALPESTRE (Hop pe) Rylands Distinguished from A. Filix-femina by the very rudimentary indusium (invisible when the sorus ,ripens), the small number of spor­ angia in each sorus, and the reticulate (not warty) markings on the spores.-A circumpolar species of the alpine and sub-alpine region which is found in the Scottish highlands.

ATHYRIUM FLEXILE (Newm.) Syme . A dwarf species. Fronds 7·5-30cm.; stalk very short (rarely more than 1 as long as the blade), bent backwards immediately above the base; blade bipinnate; lower pinnae defiexed; pinnules narrowed at the base; sori borne only on the basal part of the frond; indusium very minute, falling early.-High alpine corries in Scotland; also in France,

Genus 15. CYSTOPTERIS Bernhardi Sori round, situated on a vein which extends beyond the receptacle. Indusium sub-globose, acuminate, attached by its broad base below the sorus on its inner side only, at first covering the sorus like a hood, later reflexed.-18 species various in habit, chiefly north temperate (both hemispheres).

CYSTOPTERIS FRAGILlS (L.) Bernhardi Brittle Bladder Fern (PI. 6, Fig. 44.) Rhizome usually short 4-5 X Q·Scm., decumbent or hori­ zontal, often branched, the older parts covered with spirally arranged dead leaf bases, the younger parts, including the C. FRAGILIS 83 outermost leaf bases and the young leaves in the bud, covered with thin yellow-brown lanceolate to ovate-lanceolate acumi­ nate scales. Fronds 6-35(45)cm., in a small tuft of 5-6, dying down in winter; stalk i-j as long as blade, brittle, dark brown 'and scaly at the base, straw-yellow or green, and glabrous or with a few scales above. Blade 4·5-25(30) x 2-1O(12·5)cm., oblong-lanceolate to ovate-lanceolate in outline, acute or acuminate, thin, flaccid and delicate, bipinnate or almost tripinnate; pinnae (primary seg­ ments) up to about 15 on either side opposite or nearly so be­ coming alternate toward the apex, shortly stalked, ovate- to oblong-lanceolate, pinnate or almost bipinnate, the lowest pair Fig. 44. Brittle Bladder often somewhat distant from the Fern (Cystopteris Jragilis). others and distinctly shorter; Left: one of the lower pinnules (secondary segments) pinnules of the fourth ovate at the base of the pinna, pinna (out of 15 on one side); the lowest (aeras­ oblong toward the apex, all more copic) tertiary segment or less decurrent, the larger (basal) bears two sori; in all the ones deeply pinnatifid, the others sari the indusium has become reflexed. (x 3.) pinnately toothed, the teeth Right: small portion of obtuse or acute; tertiary seg­ a fertile frond more highly ments pinnately toothed; vena­ magnified to show the tion Pecopteridian, the venules shape of the indushlm alternate, running to the margin. before it becomes reflexed Sori in two rows one on either side (x 16).' of the midribs of the pinnules or of the tertiary segments where these are strongly developed. Indusium pale coloured, membranous ovate-lanceolate acuminate.

Fissures of moist) shady rocks and walls; common in the mountainous parts of Wales.

First recorded, 1696; Lhwyd in Ray, Syn. ed. 2, 50. 'On Snowdon.' (At one time referred to C. regia, but doubtless a variety of C. Jragilis.)

Recorded from every county in Wales except Pembrokeshire. 84 CYSTOPTERIS

Throughout the British Isles. Cosmopolitan. Mountainous districts of Arctic Europe and Asia southwards to the Himalaya and v.ia Morocco, Abyssinia and Fernando Po to South Africa and Kerguelen. Arctic North America (including Greenland) south via Central America and the Andes into Chili and via Hawaii to New Zealand and Tasmania.

Yar. DENTATA (Dick,.) Hook. Fronds bipinnate; pinnae ovate-lanceolate; pinnules ovate obtuse, bluntly and unequally toothed, rarely pinnatifid. Recorded from Mon., Glam., Brec., Rad., Mont., Caern., Denb., Flint., Angl. Specimens in Herbarium.-Mon.: Forest of Dean, nr. Monmouth, S.G.C., 1928. Brec.: Dolygaer, G.R.W., 1907. Caern.: Cwm Idwal. W.A.S., 1912.

Var. ANGUSTATA (Sm.) Koch Fronds tall, lax, bipinnate; pinnae tapering to a point; pinnules widely spaced oblong-lanceolate acute, the lowest only somewhat ovate, the larger deeply lobed into acutely toothed segments, the smaller similarly toothed. Recorded from Rad. and Caern.

Sp,ecimen in Herbarium,-Rad.: Nant Henllau, Llandeilo~graban, A.E.W., 1929.

CYSTOPTE~IS REGIA Desv. Similar to C. Jragilis but (a) leaves smaller and more finely divided and (b) teeth of the ultimate segments with few exceptions divided at the apex and the vein endings running into the re~entrant angle so formed.-North~western Yorkshire. Recorded from Caernarvonshire in error.

CYSTOPTERIS DICKIEANA Sim. Frond pinnate; pinnae deeply pinnatifid; margins of segments crenate.-Scotland.

CYSTOPTERIS MONTANA (Lam.) Desv. Rhizome creeping, about 2mm. thick; fronds at irregular intervals; stalk twice as long as blade; blade tripinnate, triangular, the lowest pinnae much the longest, the pinnulets pinnatifid.-ScotIand. Recorded from Caernarvonshire in error. W. ILVENSIS 85 Subfamily 5. WOf!DSIOIDEAE Characters of the only genus, W oodsia. Among ferns with superficial sori a line of progression may be traced from the Gleicheniaceae which have simple sori (see Appendix, p. 122) through. the Cyatheaceae which have gradate sori, to the Dryopter~ idoideae which have mixed sori, On this view, Woodsia is 'a small arctic and alpine representative of the type of Cyathea. The upright habit, chaffy scales, the pinnatioll of the leaves ... the open venation - and the basal sometimes continuously ring~like indusium, together with the signs of a gradate sequence of the sporangia, all support the comparison.' (Bower.)

Genus 16. WOODSIA Br. Sori on the backs of the veius and near their endings. Indusium surrounding the receptacle at the base, either cup­ shaped and at first wholly surrounding the sorus, separating later into ribbons (sub-genus Physematium) or split up, from the first, into narrow segments (sub-genus Eu-Woodsia, including the Welsh species). Sporangia few, gradate. Small ferns of high mountains and rocky places, with scaly rhizomes and the leaves pinnate or bipinnate with free­ ending veins, the stalk (in Eu-Woodsia) jointed some distance above its attachment to the rhizome.-38 species.

KEY TO SPECIES Blade lanceolate, pinnae oblong, with 7-13 oblong segments. Usually the larger, stouter and much more scaly plant .. 1. W. ILVENSIS Blade oblong, pinnae ovate or triangular, with 3-7 obovate segments. Usually the smaller and less scaly plant. . 2. W. ALPINA

I. WOODSIA ILVENSIS. (L.) R.Br. Oblong Woodsia (Figs. 45, 46.) Stock short, up to 4mm. thick, erect or ascending, branched, thickly clothed with the persistent leaf bases and having a few scales above. Fronds 5-10(15)cm.; stalk half as long to as long as the blade, jointed near the middle, pale reddish-brown, clothed (as is the rachis) with similarly coloured broadly subulate scales intermixed with jointed zigzag hairs. Blade 2·5-10 X O·8-3·5cm., lanceolate, oblong-lanceolate or linear in outline, obtuse to almost acute at the apex; as a rule some­ what narrowed at the base, pinnate; pinnae about 7-15 on 86 WOODSIA either side, opposite or sUb-opposite at the base, becoming . alternate towards the apex, widely spaced except at the apex, oblong to ovate-oblong, rounded at the apex, deeply pinnatifid,

Fig. 45. Oblong Woodsia (Woodsia ilvensis). Reproduced from the woodcut in Edward ~ewman's History -of British Ferns, 1854. (About X i.) with 7-13 oblong, obtuse segments, the margins of which are ciliate and (more especially on the acroscopic side) more or less crenate; rachis and under surface of pinnae densely covered w. ILVENSIS 87 with lanceolate to subulate or hair-like scales intermixed with jointed zigzag hairs; venation Pecopteridian. Sorl circular. situated on the backs of the venules, a little short of their endings. Indusium membranous, cup-shaped, basal com­ pletelybut narrowly encircling the receptacle below, its margin irregularly lobed and beset with long jointed hairs which at first completely enclose the sporangia.-For comparison with W. alpina see under that species.

Fig. 46. Oblong Woodsia (Woodsia ilvensis). Single pinna (about X 3). Damp rock crevices on high mountains; very f\lre. First recorded, 1690; Lhywd in Ray, Syn., ed. I, 27. 'Clogwyn y Garnedh [Caern.J.' Distribution"in Wales: Mer., Caerll. Very rare in Britain: only in north Wales, the north of England (Durham, Westmorland, Cumberland) and Scotland (Perthshire and Forfar). Arctic-alpine. Arctic and mountainous regions of the North Temperate zone, Northern Europe from Iceland and northern Scandinavia, scattered southwards to Switzerland, northern Italy and -the central mountains of Germany and the Carpathians. Crimea and Caucasus. Asia Minor. Northern Asia. Greenland and North America south to North Carolina, Kentucky and Iowa. Specimen in Herbarium.-Caern.: Moel Cefn, J ;A.Whe., 1942.

2. WOODSIA ALPINA (Bolton) S. F. Gray Alpine Woodsia (Figs. 47, 48.) Stock short, 2-3 X 0·2cm., upright or ascending, more or less branched, thickly clothed with persistent leaf-bases and numerous fine roots and having a few scales above. Fronds 3-IScm.; stalk i-j as long as blade, jointed near or below the middle, pale reddish-brown, with a few broadly subulate scales near the base. Blade 2-10 X 0·8-2·Scm., linear-lanceolate to lanceolate, bluntly poiuted to rounded at the apex, not always

G 88 WOODS lA narrowed at the base, pinnate; pinna~ about 8-12 on either side, usually opposite or sub-opposite, and (in strong plants) wide apart at the base becoming alternate and closer together toward the apex, ovate or triangular, pinnatifid, with 3-7

Fig. 47. Alpine Woodsia (Woodsia alpina). Reproduced from the woodcut in Ed'Yard Newman's History of British Ferns, 1854 (about X i). rounded,. entire or faintly wa vy-margined segments; rachis and under surface 'of veins and edges of pinnae with a few narrowly subulate to hair-like scales intermixed with zigzag jointed hairs; venation Pecopteridian. Sori and indusia as in W. ilvensis.-Resembles W. ilvensis very closely but the fronds are smaller, narrower and more delicate and have fewer 'scales; the pinnae also are ovate in: outline, whereas in W. ilvensis they are oblong. W. ALPINA 89 Damp rock crevices on high mountains; very rare. First recorded, 1790; Knowlton in Bolton, Filices Brit., Pt: 2, 76. 'From the mountains of Wales.' In Wales found only in Caernarvonshire. Very rare in Britain: only in north Wales and Scotland (Perthshire, Forfar, Argyle and the Inner Hebrides).

Arctic~alpine. Arctic and mountain regions of the North Temperate zone. Europe from Scandinavia and northern Russia southwards to the Pyrenees. northern Italy and the Carpathians. Ural Mountains, northern Asia and north-central Asia to the Altai. Green­ land and North America from Labrador to Alaska southwards to New York and Fig. 48. Alpine Woodsia western Ontario. (Woodsia alpina). Specimens in Herbarium.-Caern.: Single pinna (about Moel Ogof, J .E.G., 1884; above Crib X 5). Goch, W.!" 1895. Subfamily 6. DRYOPTERIDOIDEAE Sori superficial usually on the backs of the veins (sometimes at their ends), usually round; indusium usually present, vari­ able in form and position, but typically superior springing from the centre of the raised receptacle and opening outward toward the margin of the pinna or all round. Sporangia mixed.~ Mostly terrestrial ferns with erect stock or creeping rhizome covered with broad soft scales; leaves not jointed to the rhizome, of very diverse habit, venation and degree of hairiness, but the fertile leaves usually indistinguishable from the sterile.

This subfamily may be regarded as having been derived from ancestors related to the tree-fern genus Cyathea: the most important advances having been that from a gradate to a mixed sorus and the change-over in the indusium from a basal cup to a lop-sided cover. Both these features are realized in Male Fern: further evolution has resulted in the circular.peltate indusium of Polystichum followed by the ·complete loss of the indusium (as in Gyiftnocarpium) and the spread of the sorus along the vein. Groups of species in the European fern flora may conveniently be distinguished by the characters of the indusium; and in the older British floras such groups are recognized ·as genera. Thus the species we have placed under Dryopteris, together with two we have placed under Thelypteris, all have a reniform indusium, and consequently were grouped formerly under the genus Lastrea. Again, the species now included in Gymnocarpium, as also Thelypteris Phegopteris, have no indusium, ,and in consequence were formerly included in the genus Polypodium. But research on the 'world flqra has shown that these old 'genera' are not natural groups; other critena are now emplo-yed and more truly natural genera have been delimited. These have been grouped in two tribes. 90 DRYOPTERIS

Tribe I. DRYOPTERIDEAE Rhizome and leaves markedly scaly, with often very numerous large and broad to hair-like s<;ales; the rachises. very rarely with simple grey hairs. Leaf·stalk with 4-7 or more vascnlar bundles. Veins free or (in some foreign groups) variously united, the free ones ending in water-glands within the margin. Sporangia never provided with bristles.

Genus 17. DRYOPTERIS Adanson (em. C. Chr.) Buckler Ferns. Sari generally large with large reniform indusia. Rhizome usually oblique or erect and densely clothed with broad soft often lacerated scales. Leaves tufted,. mostly' of thick somewhat fleshy texture and light green colour, lanceolate and bi­ Fig. 49. Male Fern pinnatifld, or triangular bi- to tri-pinnate- (Dryopteris Fili%.- and with unequal-sided pinnae having fertilemas). Partsegment of a t h'elT Iargest b asaI pmnu. I es on th'de SI e (x 13), showing a away from the frond apex. Veins free,. single sarus at an as a rule forked, the midribs decurrent.­ e~dy stage, still About 150 species mostly in the North almost entirely . . t A . covered by the kid- Temperate regIOn, many 'm eas ern sm ney-shaped indus- and Africa, few in Tropics. ium.

KEY TO SPECIES A Stalk stout, less than t as long as blade; 'teeth of pinna segments not spinulose~mucronate B Leaves pinnate, pinnae deeply pinnatifid C Stalk and rachis not densely clothed with golden-brown scales D Pinna segments fiat. Indllsium not. glandular 1. D. FILIX-MAS DD Pinna segments concave. Indusium glandular 2. D. ABBREVIATA CC Stalk and rachis densely clothed with golden-brown scales .. 3. D. BORRERI BB Leaves bipinnate 4. D. VILLARSII AA Stalk narrow and brittle, more than t as long as . blade; teeth of pinnules spinulose-muc- ronate E Leaves pinnate (seldom bipinnate at base) 5. D. CRISTATA EE Leaves (at least lower part) bi- to tri-pin- nate F Scales with a dark central stripe. . 6. D. DILATATA FF Scales uniform in tint G Indusium entire, non~glandular. . . 7. D. SPINULOSA GG Indusium jagged, glandular 8. D. AEMULA D. FILIX-MAS 91

I. DRYOPTERIS FlLIX-MAS (L.) Schott (Lastrea Filix-mas (L.) Presl) Male Fern (Figs. 1-7.49, 50.) Stock stout. up to ZO x Z-Z·5cm., erect or ascending, the older part densely covered with spirally set blackish-brown dead leaf bases, the younger parts thickly clothed with chaffy scales similar to those of the full-grown leaf stalk. Fronds 35-150cm., arranged in a basket-like manner, usually dying in winter; stalk i-t as long as blade, sparsely or moderately clothed with pale-brown, linear- lanceolate to ovate-lanceolate, cordate, hair-pointed scales of various sizes up to 1·5 X 0·5cm. Blade 30-125 X 10- 30cm., firm, dark green above, paler below, lanceolate, pinnate; pinnae about 20-35 on either side, sometimes sub-opposite at the base, otherwise alternate, sessile Of. nearly so, linear­ lanceolate, truncate at the base, usu­ ally acuminate, deeply pinnatifid (al­ most to the rachis); pinna segments alternate (except the lowest pair on each pinna), touching by their broadened -bases, oblong, rounded at the apex, serrate (rarely deeply so or even lobed) along the margin (the teeth Fig. 50.. Male Fern not spinulose); venation Pecopteri­ (Dryopteris Fili:Nnas). aian; rachis and lower sides of midribs Single fertile segment from a median pinna sparsely scaly, or sometimes without (X 6). scales. Upper third of the frond only as a rule fertile. Sori on the acroscopic branch~s of the secondary veins and forming two lines near and parallel with the midrib of the segment. Indusium large, convex, reniform, with a deep notch, not glandular, persistent, the margin lying flat on the surface of the leaf when young. Common in woods, woodland clearings and hedge-banks. First recorded 1726; Herb. Dillenius, 'prope Dolegelle [Dol­ gelley, lVIerionethJ.' (Druce and Vines, The Dillenian Her­ baria, 47, 1907.) Recorded from every county in Wales. Throughout the British Isles. North Temperate zone of the Old Wodd. 92 DRYOPTERIS

2. DRYOPTERIS ABBREVIATA (DC) Newm. (Dryopteris Filix-mas vaT. abbreviata (DC.) Newm. Lastrea propinqua Wollaston). Dwarf Male Fern As D. Filix-mas 'except :-Stock when mature branched and tufted. Fronds usually 50 cm. or less, stiff; stalk densely scaly, the largest scales ovate, not hair pointed. Blade with minute glands beneath; pinnae with upcurled tips and edges; pinna segments sinuate-crenate or crenately lobed; the teeth broad, obtuse, the apex less deeply toothed or subentire; lowest acroscopic pinna segment longer than its adjacent neigh­ bour; rachis with pale-brown linear- to ovate-lanceolate scales. Sori 2-4 on each side of the midrib of the longest pinna seg­ ments, though only 2 or 1 on the majority. Indusium with minute glands on the margins. . In rock crevices and on screes in mountain districts. Recorded from 1\'Ier. and Caern. Mountainous regions of England and Scotland; Ireland. Foreign distribution imperfectly known. Specimen- in Herbarium.-Mer.: above Harlech, P.W.R., 1951.

3. DRYOPTERIS BORRERI Newm. (Dryopteris Filix-mas var. paleacea (Don) pr. Lastrea pseudo­ mas Wollaston). Golden-Scaled Male Fern

AsD. Filix-mas except:-Stalk and rachi~ shaggy with orange­ yellow to golden-brown, linear-lanceolate to ovate-lanceolate, acuminate scales. Fronds somewhat leathery, yellowish-green, glossy, persisting until late in season. Pinnae (when living) with a dark brown or blackish patch' near their junction with the rachis; pinna segments straight- and almost parallel-sided, subtruncate and with a few, sharp, triangular teeth at the apex, the rest of the margin sub-entire. Sori 3-5 on each side of the midrib. Indusium with margin tucked under the sorus. Common in hedgebanks, woods, and woodland clearings. Recorded from Mon., Glam., Brec., Carm., Pemb., Card., Mont., Mer., Caern. Throughout the British Isles. Norway, Western and Southern Europe. South-west Asia northwards to the Caucasus. D. VILLARSII 93

4. DRYOPTERIS VILLARSII (Bello) Woynar (Lastrea rigida Presl) Rigid Buckler Fern (PI. 6, Fig. 51.) Stock,10cm., horizontal to ascending, the older parts densely clothed with blackish-brown dead leaf bases (the whole up to Scm. thick), and the younger with numerous brigllt brown narrow lanceolate scales. Fronds 20-60cm., numerous, tufted, erect or spreading, fragrant, in all their parts above and below more or less richly covered with short yellowish glandular hairs; stalk usually up to about t as long as or rarely as long as the blade, thickened and dark brown at the base, otherwise (like the rachis) straw-yellow to greenish-yellow, clothed (densely at the base, more sparingly so higher up) with lanceo­ .late to ovate-lanceolate hair-pointed reddish-brown scales, the larger ones intermixed with numerous smaller and narrower, sometimes hair-like ones. Blade 15-40 'X S-13cm., lanceolate to narrow triangular in outline, dull green above, paler beneath, bipinnate; pinnae up to about 25 on either side, lower pairs opposite or sub-opposite, higher ones becoming alternate, the lowest pair ,the longest, the remainder gradually Fig. 51. Rigid Buckler Fern (Dryopteris Villa1'­ shortening to the apex, the lowest sii). Single pinnule from lanceolate to ovate-lanceolate, the a median pinna (x 6). remainder gradually narrowing to oblong-lanceolate, all shortly stalkec!, pinnate; pinnules opposite becoming alternate, the lowest very shortly stalked, the remainder sessile becoming decurrent, all in outline mostly oblong, obtuse Of sub-acute more or less deeply crenato-pinnatifid, the lobes typically rounded in outline with 6-1 acute but not spinulose teeth; venatiou Pecopteridian; raehises with numerous pale lanceolate or subulate scales. Sori large, round, arranged in two rows on each fertile- pinnule, one on either side of the midrib, mostly situated on the lowest acroscopic tertiary venules, crowded and with the,illdusia touch}ng or overlapping. Indusium convex, roundish-kidney-shaped, its surface and margin glandular. 94 DRYOPTERIS

D. Villarsii is easily distinguished by its balsam-like fragrance, the numerous glands all over the frond and the rieat crenately-Iobed pinnules. Crevices of limestone rocks in mountainous districts; very rare. First recorded, 1868; G. R. Jebb, in Science Gossip, 139. 'North of Llangollen, Denbighshire.' Distribution in Wales: Caern. and Denb. In Britain only in north Wales and the north·west of England. In the rest of Europe in the Alps and neighbouring ranges from southern Germany to the Pyrenees, the Mediterranean region and Bulgaria. Asia Minor to Afghanistan. Specimen in Herbarium.~Caern.: Cwm Idwal, J .E.G., 1884.

5. DRYOPTERIS CRISTATA (L.) A. Gray (Lastrea cristata (L.) Presl) Crested Buckler Fern Rhizome decumbent or creeping, Fronds in an open tuft, sterile (shorter-up to 45cro.-somewhat spreading) distinct from fertile (taller-up to IOOcm.-erect); stalk! as long as sterile blade, i-I as long as fertile, when mature with broad pale scales at the base only. Blade linear-lanceolate, glabrous, pinnate; pinnae short ,triangular oblong, shortly stalked, pinnatifid, the lowest pair not shorter than the next; segments oblong usually rounded at the apex, serrate-mucronate, attached by their whole width and connected at the base, the lowest pin­ nately lobed, the acroscopic and basiscopic segments of the lower pinnae nearly equal. Fertile pinnae with their stalks twisted so that their upper surfaces are directed toward the apex of the frond. Sorl forming two rows about midway between the mid-vein and the margin of each segment. Bogs and wet heaths. England (mainly eastern) and south-west Scotland. Rare. Circumpolar. Northern and central Europe. Caucasus, western Siberia and Japan, eastern North America from Newfoundland to Saskatchewan south to Arkansas.

6. DRYOPTERIS DILATATA (Hoffm.) A Gray (D. aristata (ViII.) Dr. Lastrea dilatata (Roffm.) Presl) Broad Buckler Fern (PI. 7, Fig. 52.) Stock stout, ascending or upright, almost stem-like, some­ times branched, the older parts thickly clothed with brownish­ black dead leaf bases, the younger parts with light brown lanceolate scales having a darker brown or almost black central stripe. Fronds (JS)30-1S0cm., tufted (basket-like when the stock is erect); stalk about f as long as blade, dark purplish­ brown below to straw-coloured or pale green above, densely clothed at the base,' and somewhat less so higher up, with Plate 7. Left: ~ARROyV BUCKLER TTIRN (Dl'yojJteris sj)inulosa) IVlidclle; HAY-SCENTED BUCKLRR .FERN (D. aemula) Right: BROAD BUCKLER FERN (D. dilatata) Plate 8. Left: HARD SHl£LD FERN (Polystichum w;uleaturn) Right: SOFT SHIELD FERN (P. setijerum) D. DILATATA 95

lanceolate light brown scales with a dark central stripe. Blade (10)20-90 x (7)15-40cm .• triangular- to lanceolate-ovate in outline (not narrowed at the base). dark green above and glandular on' the veins, paler beneath, bi- or tri-pinnate; pinnae up to 25 on either side, stalked, the lower ones opposite Or sub-opposite, the upper­ most ,. Dues only becoming alternate, the lowest pair unequally triangular in out­ line and as long as or slightly longer than the succeeding pair, the remaining pinnae becoming less unequal and more nearly lanceolate; pinnnles alternate, oblong­ ovate to oblong-lanceolate, pinnate or pinnatifid, the basal ones stalked, the re­ mainder sessile or decurrent, the lowest acroscopic pin­ mile of the ·lowest pinna somewhat shorter than the next succeeding pinnule and only about half as long as the lowest basiscopic pinnule of the same pinna; pinnnlets (and other segments of the third order) ovate to oblong, coarsely toothed, the teeth mucronate and incurved toward the apex of the pin­ Fig. 52. Broad Buckler Fern (Dryopteris dilatata). Median nule; venation Pecopter­ pinnule from a pinna in the upper idian; rachises with scattered part of an average frond (X 6). scales and either with stalked glands or otherwise glabrous. Sori numerous, round, in two rows one on either side of the midrib, and somewhat nearer it than the margin of the pinnulets or pinnules, each individual sorus on the acroscopic fork of a secondary vein. Indusium reniform, prominent, convex, its margin usually dentate and sometimes glandular.-For points of distinction from D. spinu­ losa see under that species. Common in moist woods and thickets, and on bedgebanks and Shady mountain rock ledges. First recorded, 1726; Herb. Dillenius. 'Cumglas [Cwm Glas] in monte Snodon [Snowdon, Caern.].' The specimen is 96 DRYOPTERIS apparently the var. dumetorum. (Druce and Vines, The DiUenia.n Herbaria., 49, 1907.) Recorded from every county in Wales. Throughout the British Isles. Circumpolar. Throughout almost the whole of Europe. Asia Minor. Cyprus. Madeira. Northern Asia. Japan. Greenland and North America from Alaska and Newfoundland southwards to California,. Tennessee and North Carolina. South Africa. The di'3tribution of this species and D. spinulosa is incompletely known as the two species have not always been treated as distinct.

Var. TANACETIFOLlA (Hoffm.) Frond large; blade sub-triangular, ovate to broadly ovate in outline, tripinnate; pirinulets ovate-oblong, pinnately toothed (the smaller segments toothed only at the apex); indusium small. Probably to be regarded merely as a luxur­ iant state of the 'type.' Recorded in Wales from Glam.

Var. DUMETORUM (Sm). Fronds small, seldom over 30cm.; blade oblong-ovate or triangular-ovate in outline, bipinnate; stalk, rachises and under surface of veins clothed with glands; pinnules oblong; sari large; indusium fringed with stalked glands. Recorded in Wales from Rad., Mer., and Caern.

Var. NANA (Newm.) Fronds small, 7-17 X 6-12cm.; blade ovate or triangular­ ovate in outline, bipinnate, somewhat glandular; pinnules convex. Indusium small, with a slightly glandular margin, shed early. Recorded iu Wales from Caern .. Specimens in Herbarium.-Caern.: Cwm Glas, J.E.G.; Cwm Llafar, J.E.G., 1893.

Var. ALPINA (Moor.) Blade narrow,- linear-lanceolate in outline, thin and rather delicate in texture, bipinnate; lowest pinnae very unequally deltoid, the rest becoming gradually less so. Sari large, numerous; indusium small, with a ragged glandular margin, shed early. D. DILATATA 97

Recorded from Glam. ; also from Caern. by Griffith (Flora), whose specimens do not, however, agree with Maore's descrip­ tion but with that of var. nana. The same remark applies to certain other specimens in the Herbarium named var. alpina, which suggests that this variety has been misunderstood. Specimen in Herbarium.-Glam.: Rudry Common, J .L.M., 1939. Var. eoUina (Newm.). Recorded from Caern. by Gdffith (Flora), .. but his specimens do not agree with Maore's figures . 7. DRYOPTERIS SPINULOSA (MulL) O. Ktie. (Lastrea spinulosa (MUll.) Presl) Narrow Buckler Fern (PI. 7, Fig.. 53.) Stock short. up to 10 'X 3-4cm., decumbent or horizontal, very scaly, the older parts clothed with dead leaf bases. Fronds 30-120cm., few, not forming a basket-like tuft; stalk about equal to the blade in length, relatively thin, dark brown billow and pale above; clothed at the base and be.. 'strewn here and there above with pale brown ovate to ovate-lanceolate, cordate, hair-:-pointed scales having no dark central portion. Blade 15-60 x 1O-2Scm., oblong-lanceolate to lanceolate (but not narrowed at the . base) or. rarely ovate-oblong in outline, light to yellowish-green, glabrous except rarely for minute glandular hairs on the under surface, bipinnate ; pinnae about IS-20 on either side, shortly stalked, the low­ est pairs opposite or sub-opposite, the uppermost only alternate, the lowest pair unequally triangular in Fig. 53, Narrow Buckler . outline and usually a little shorter Fern (Dryopteris spinu­ than the next pair above, the upper losa). Median pinnule pinnae becoming more nearly from third or fourth lanceolate; pinnules, pinna of an average­ oblong-ovate sized frond (x 6). decurrent, the basal ones deeply pillnatifid, the rest becoming less and less deeply cut toward the apex of each pinna" the basiscopic pinnules of the lowest pinnae larger than the acroscopic ' ones; ultimate segments ovate-oblong pinnately toothed, the 98 DRYOPTERIS teeth spinulose-mucronate and incurved; venation Pecopteri~ dian; rachises with scattered subulate scales. Sorl numerous, mostly on the acroscopic forks of the secondary veins of the pinnules and rather nearer to the midrib than to the margin of the pinnule, or, in the larger tertiary segments, forming two rows on the lower secondary veins of those segments. Indusium rounded-reniform, its margin entire, wavy or slightly toothed, rare1y with a few stalked glands. D. spinulosa may be distinguished from D. dilalala (a) by .. the colouring of the scales on the stalks: dark in the centre and pale at the margins in D. dilalala and uniformly pale throughout in D. spinulosa (b) by the margin of the indusium: usually fringed with glands in D. dilalala, very rarely so in D. spinulosa. Locally frequent in damp woods and shady places. First recorded, 1813; Davies, Welsh Bot., pt. I, 98. Bodafon Mountain, Anglesey. Distribution in Wales: Mon., Glam., Brec., Carm., Card., Mer., Caern., Flint., Angl. Throughout the British Isles, thinning out in the north. Circumpolar. Widely distributed in the North Temperate zone. Korthern and central Europe to the Mediterranean region and the Caucasus (absent from the northernmost parts of Scandinavia and Russia). Northern Asia to Manchuria. North America from Alaska and Labrador southwards to Idaho, Kentucky and Virginia. -Specimens in Herbariuill.-Mon.: nr. Chepstow, W.A.S., 1889; Barnets Woods, W.A.S., 1893; Piercefield Woods, W.A.S., 1895; Beaulieu Wood, S.G.C., 1924; Redding's EncloSure, Taren yr Esgob and Troy Park Wood, S.G.c., 1941; Talycoed, S.G.C., 1943; White~_ brook and Giosmont Wood, S.G.C., 1944. Brec.: Llanwrtyd Wells, W.H.P., 1900. Mer.: Llanbedr, J.F.P., 1901. Caern.: lll". Bangor, J.E.G" 1884. Angl.: D". Holyhead, J .L.C., 1857.

Var. EXALTATA (Braun) Dr. Frond large up to 90X IS-20cm., stalk about as long as the oblong-lanceolate, dark green blade; pinnules somewhat widely spaced. Indusium nearly entire, without glands. Recorded from Mon. V.r. DECIPIENS (Syme) Dr. Blade oblong or bblong-Ianceolate, firm, yellowish-green,' with minute club-shaped glands beneath; rachis sprinkled with minute stalked glands. Indusium toothed, usually without glands. Recorded from Mon. and Glam. Specimens in Herbarium.-Mon.: nr. Tintern, A.L., 1892; between Tintern and Trelleck, A.L. and W.A.S., 1893. D. AEMULA 99

8. DRYOPTERIS AEMULA (Ait.) Kuntze (Lastrea aemula (Ait.) Brack. L. Foenisecii Wats.) Hay-scented Buckler Fern (PI. 7, Fig. 54.) Stock stout, erect or ascending, the older parts clothed with the baBes of dead fronds, the younger with narrow-lanceolate uniformly pale brown sometimes lacerated erect scales. Fronds 15-60cm., numerous, tufted, fragrant with the smell of new-mown hay; stalk as long as blade, rigid, brownish-purple, clad (densely below, sparingly above) with narrowly lanceolate to ovate uniformly rusty-brown sometimes lacerated scales. Blade 8-30 x 4-20cm., triangular to ovate-lanceolate in outline, bright green· above, paler beneath, both surfaces sprink­ led with minute sessile glands, bipinnate (to tripinnate at the base); pinnae about 15-20 on either side, stalked, the lowest pairs opposite or sub-opposite, the uppermost only alternate, the lowest pair unequally tri­ angular and distinctly the long­ est, the rest lanceolate to' linear-lanceolate, all acute; pinnules alternate, oblong, the basal ones stalked, the remainder , sessile and becoming decurrent, pinnate becoming pinnatifid and ultimately only toothed, the lowest basiscopic pinnnle of the lowest pinna on either side twice as long as the lowest acroscopic pinnule on the same pinna and Fig. 54. Hay-scented Buckler Fern (Dryoptens aemula). unlike the rest usually broadly Median pinnule from second lanceolate in outline; ultimate or third pinna of an average­ segments (whether pinnulets or sized frond (X 6). pinnules) oblong, the margins up­ turned (producing a crisped appearance) and pinnately toothed, the teeth not or only slightly incurved toward the apex of the segment, somewhat coarse and shortly mucronate; vena ... tion Pecopteridian; rachises bearing scattered lanceolate _ scales with hair-like points. Sari in two rows on the ultimate segments, one on Oither side of the midrib and somewhat 100 DRYOPTERIS nearer to it than to the margin, each individual. sorus on the acroscopic fork of a secondary vein. Indusium reniform, the margin jagged and beset with sessile glands. Shady, rocky places, especially about streams and in rocky woods; rare. First recorded, 1844; Newman, Hist. Brit. Ferns, ed. 2, 228. 'Merionethshire.' Newman refers Filix montana ramosa argute denticu/ata, Ray, Syn., 27, 1690, from the Glyder, Caern., to this species. Distribution in Wales: Glam., Carm., Pemb., Mer., Caern., Flint., Angl. Iri Great Britain chiefly in the west; in Ireland almost throughout. British Isles. North-western France. Spanish Galicia. Azores and Madeira. Speci~ens in Herbarium.-Carm.: Pumpsaint, H.H.K'J 1907. Mer.: nr. Barmouth, B., 1863; Rhaiadr Du, S,P.R., 1933. Caern.: ur. Bangor, C,W., 1876; Cwm Idwal, J,E.G., 1878; Beddgelert, J,B.S., 1925, HYBRIDS IN THE GENUS DRYOPTERIS D. Filix-mas X D. spinulosa (X D. remota (Braun)). Differs from,D. Filix-mas in the longer stalk, broader blade, almost completely pinnate pinnae and spinulose-mucronate teeth; from D. spinulosa in the shorter stalk, narrower blade, narrower less divided pinnae and shorter-pointed teeth; (also from D. Villarsii in the lack of glands). Highly sterile.*-Very rare. Westmorland. Germany. U.S.A. D. cristata X D. spinulosa (X D. uliginosa (~ewm.) Druce). Resembles D. cristata in general appearance, differing in the bi- or tri-pinnate leaves and the greater acuteness of the lower pinnae. Highly sterile.*-Rare. Cheshire, Notts., Norfolk. Europe and North -America. D. dilatata X spinulosa. Rhizome semi-erect, scales dark-striped, frond narrowish with lowest pinna shorter than the one above.-England, Scotland, Ireland, Con­ tinental Europe. (Manton, 1950.) ,

Genus 18. POl YSTICHUM Roth Sori globose, .situated on the backs of the veins, rarely at the ends. Indusium circular, peltate, attached by its centre to the apex of the receptacle. Handsome ferns with (in our species) Fig. 55. Soft Shield short erect stock and abundant broad Fern (Polystichum soft scales; fronds tufted, short stalkecl ; "tiferum). Pact of blade mostly stiff and leathery, simply a fertile pinnule (X 13), showing pinnate to tripinnate with distinctly un- a single sorus. equal-sided pinnae having their largest

>I< Sterili ty is here due to spore abortion (which in its turn arises from irregularity of chromosome pairing) and confirms the supposed hybridity. Manton, Brit. Fern Gazette, VII, 165. 1938. P. SETIFERUM 101

basal pinnules (or lobes) on the side nearer to the frond apex, the ultimate segments with acuminate bristle-pointed teeth; venation Pecopteridian to Neuropteridian.-About 225 species. KEY TO SPECIES Fronds bipinnate Fronds flaccid; basal pinnules of lower pinnae with more or less obtuse-angled base, shortly stalked ...... ,LP. SETIFERUM Fronds stiff; basal pinnules of lower pinnae with an acute-angled wedge-shaped base, sessile 2. P. ACULE.U'UM Fronds pinnate 3, P. LONCHITIS

I. POLYSTICHUM SETIFERUM (Forsk.) Woynar (P. angulare (Kitaib.) Presl) Soft Shield Fern (PI. 8, Figs. 55, 56.) Stock ascending or erect, up to IOcm., thick, woody, surrounded by the dead bases of old fronds, the younger parts clothed with scales . similar to those on the leaf­ stalks. Fronds 30-1 20cm. , arranged in a basl;:et-like manner, spreading and more or Ie:ss drooping, winter-green in sheltered places; stalk l: to t as long as the blade, markedly channelled on its inner (upper) face, dark brown at the base, green above, densely clothed es­ pecially at the base with large pale-brown ovate-lanceolate Fig. 56. Soft Shield Fern (Poly­ acuminate scales intermixed stichum setiferum). 'Median pin­ nule from a medi~n pinna (X with smaller hair-like scales 5i)· and adpressed ciliate scurf­ like ones. Blade 20-100 X 9-25cm., lanceolate in outline, rather thin in texture. soft and flaccid when young, its upper surface rich green, the under surface paler and often bluish-green with scattered hair-like scales, bipinnate; pinnae up to 40 on either side, opposite or sub-opposite becoming alternate or alternate almost throughout, shortly stalked, linear-lanceolate in 102 POLYSTICHUM outline, unequally broad-based, pinnate, the upper pinnae pinnatifid or pinnately toothed and varying from lanceolate to sickle-shaped; pinnules shortly stalked (except where they run together toward the apex of the pinna) obliquely ovate or somewhat crescent-shaped, obtusely angled and very unequal at the base (broadly truncate and usually with a well marked lobe on the side toward the pinna-apex, cuneate on the other) acute or rounded at the apex, deeply serrate with long hair-pointed teeth along the margin; basal acroscopic pinnule usually longer than the rest and, together with other adjacent pinnules, sometimes deeply pinnatifid; venation Pecopteridian, only those venules which bear sari not ap­ proaching the margin; main rachis shaggy with scales and hairs like those of the stalk, rachises of the pinnae with hair­ like scales only, all with a narrow well-marked channel down the middle of the upper surface. Sori small, round, usually confined to the upper half of the frond, situated on or near the endings of (mostly) tertiary venules and forming a line on either side of the midrib of each pinnule and also of that of its basal lobe. Indusium circular, peltate.-For comparison with P. aculeatum see under that species. Woods and he.dgebanks; frequent in the south, less so in the north. First recorded, 1842; *Gutch. in Phyt., I, 380. 'Hedge going from Swansea to Cromlyn [CrymlynJ Bog.' Recorded from every county in Wales. In England and Wales, thinning out eastwards; southern Scotland thinning out northwards (apparently absent in ;the extreme north) ; throughout Ireland. . Elltope, chiefly western and southern from Great Britain to the lVlecliterrancan region. Distribution outside Europe doubtful owing to confusion with related species. ~pecimcns in Herbarium.-Mon.: between Triley and Crowfield, A.E.W., 1925; -St. Arvans, A.KW., 1931; nr. Monmouth (6), Llan­ denny and Penallt, S.G.C., 1941; nr. Cross Ash, Cwmyoy and Gros­ mont, S.G.C., 1942; Llanthewy Fach, A.E.W., 1943; Llandogo, S.G.C., 1944; nL Pandy, S.G.C., 1945. Glam.: Bishopston Valley, J.A.W., 1923; Mumbles, V.M.P., 1929. Rad.: nr. Craig-pwll-du, A.E.W., 1929. Carm.: Llan?overy, H.H.K., 1907; nr. Carmarthen, J.W.W., 1915; between Kldwelly and Mynydd y Gareg, A.E.W., 1930 ;,·St. Ishmael, J,A.W., 1941. Pemb.: Tenby, J.G., 1924. Card.: nr. Newquay, J .W.W., 1911. Mont.: nr. Dolganog, J .A.W., 1940. Mer.: nr. Harlech, J.A.W., 1940. Caern.: nr. Conway, J.B,W., 1841; nr. Llandudno, W,H.R., 1861; Bethesda, J .E.G., 1880. Angi.: Wern, Red Wharf Bay, H.A.H., 1926.

* In Flower and Lees, Additions to the List of Plants met with in the neighbourhood of Swansea, I.e. 377-80. P. SETIFERUM 103

Var. HASTU LATUM (Ten.) Dr. Lowest pair or pairs of pinnules pinnatifid to pinnate and in particular the acroscopic basal lobe of the lowest pinnule free to the midrib; fronds usually large. Recorded from Pemb. and Caem. Specimens in 'Herbarium.-Pemb.: Tenby, J .G., 1924. Caern.: Tremadoc, j.L.W., 1891.

2. POLYSTICHUM ACULEATUM (L.) Roth (P. lobatum (Hucis.) Woynar) Hard Shield Fern. (Pl. 8,, Fig. 57,) Stock similar to that of p, setiferum, Fronds 30-90cm" arranged in a basket-like -manner, rigid, erectish or more or less spreading, generally winter-green; stalks usually about t as long as blade, densely clothed especially at the base with large brown ovate-lanceolate acuminate scales, sometimes inter­ mixed with some hair-like and/or some scurfy scales, Blade 25-75 X S,S-22cm" lanceolate in outline, narrowed above and below, firm in texture, stiff, its upper surface dark to yellowish-green, somewhat glossy, the under surface paler with scattered hair-like scales, pinnate or bipinnate; pinnae up to about 50 on either side, opposite or sub-opposite below, becoming alter­ nate, or alternate -almost throughout, very shortly stalked, unequal at the base, linear, lanceolate acuminate to Fig. 57. Hard Shield ovate-lanceolate in outline, pinnate in Fern (Polystichum the lower half of the frond and pinna- aculeatum). Second 'd h pinnule of a median ·tifi d above or pinnabfi t roughout, pinna (X Si), becoming less divided toward the. apex of the frond and ultimately sickle-shaped, simple and toothed; pinnules or segments sessile and all but the lowest decurrent, ·mostly incurved toward the apex of the pinna, narrowly and obliquely ovate-lanceolate or oblong, very unequal at the base (much broader and almost truncate on the side toward the pinna apex, cuneate on the other, but as a whole more acutely H 104 POLYSTICHUM angled than in P. setiferurn) rather suddenly acute with a long bristle at the apex, serrate with shorter bristle-pointed teeth alon~. the margin (except toward the base) ; . the first acro­ SCOPIC segment of each pinna with its edge flattened to the main rachis, much larger than the rest, and with a strong tri­ angular long-bristle-pointed acroscopic lobe at the base, this lobe being less often developed (though more weakly) also in the remaining pinnulcs or only represented by the long bristle or not at all; venation Pecoptehdian; rachises clothed with broadly lanceolate scales intermixed with narrowly subulate to hair-like ones. Sori small, usually confined to the upper half of the frond, situated much below the vein endings and forming a line on either side of the midrib of each pinnule and also that of its basal lobe. Indusium circular, peltate. P. aculeatum may be distinguished from P. setiferum by means of (a) the stiff leathery rigid fronds, (b) the pinnules which more often run together or if distinct are sessile and usually acute not obtuse at the base, (c) the fertile veins which run beyond the sori right to the margin of the segment. Hybrids between the two species exist. Woods and shady hedge banks and on shady rock ledges in mountainous districts; frequent to common in the south, rarer in the north. ' First record, 1696; Lhwyd in Ray, Syn., ed .. 2, 48. , ... in monto@s Cambrobritannicis.' This record is of the vaT. cambricum. Recorded from every county in Wales. Throughout the British Isles. Europe, almost throughout, but not northern Scandinavia and only south-western Russia. Distribution outside Europe doubtful owing to confusion with related species. Specimens in Herbarium.-Mon.: Mounton, W.A.S., 1891; Great Dinham, W.A.S., 1908; nr. Glascoed, A.E.W., 1924; Lilyrock Wood, S.G.C., 1926; Garth vVood, S.G.c., 1928; Redding's Enclosure, S.G.C., 1937; Llanthony and Cwmyoy, S.G.C., 1940; Lady Park Wood, S.G.c., 1940; Lla.ndenny, S.G.C., 1941; nr. Newcastle, S.G.C., 1942; Cross Ash, S,G.C., 1944; Taren yr Esgob, A.KW., '1944; nr. G-rosmont, S.G.C., 1945. Glam.: Cyfartha. 'Woods, G.R.W., 1910; Cefn On, A.E.W" 1920; Perddin Valley, A.E.W., 1925; Coed Cefn On, B.A.B., 1941. Bree.: Cwm Taf-fechan, G.R.W., 1907; Tredllstan, A.E.W., 1925; Ffrwdgrikh Falls, A.E.W., 1926; Dyffryn Crawnon, A.E.W., 1929; nr. Capel y ffin, S.G.C., 1939; raren yr Esgob, Pen. y Gader and nr. Pont Rhyd Goch, S.G.C., 1941. Rad.: nr. Walton, A.L., 1905. Carm.: Llandovery, H.H.K., 1907 and ],F.]" 1927. Mont.: Kerry Valley'and Fronlraith, ] .A.W., 1939. Caern.: Llandegai, C.W., 1876; Moel Hebog, ] .E.G., 1891. Flint.: The Leete, C.Wa .• 1910 and] .D.M., 1934. Angl.: Cadnant Dingle, ] .E.G" 1882. P. ACULEATUM 105

Var. CAMBRICUM (5. F. Gray) (Var. lonchitidoides (Hook.) ) Almost all pinnae simple obliquely ovate or sickle-shaped, and coarsely toothed with a marked basal acroscopic lobe. This var. is liable to be mistaken for P. Lonchitis, but may usually be distinguished therefrom by (a) the two distinct lobes, basiscopic as well as acroscopic, at the base of the lowest pinnae, (b) the relatively coarse main serrations which are almost lobes, (c) the sharp teeth in between or on the sides of the main serrations. Distribution in Wales: Mon., Glam., Brec., Caern. Specimens in Herbarium.-Mon.: Mynydd Maen, T.R,T. Glam.: nr. Llwydcoed, Aberdare, H.!.J" 1934. Caern.: Cwm Glas, J.E.G" 1880.

3. POLYSTICHUM LONCHITIS (L.) Roth Holly Fern (PI. 9, Fig. 58.) stock short, thick, ascending, densely covered with the dead bases of old fronds, the younger part clothed with scales

Fig. 58. Holly Fern (PolystichumLonchitis). Median pinna from an average-sized frond ,( X 3). similar to those of the leaf stalks. Fronds 15-60cm., tufted, winter-green; stalk about i as long as the blade, clothed especially toward the base with ovate or ovate-lanceolate brown scales, large and small intermixed. Blade 12-50 x 2--6cm., linear-lanceolate in outline, tapering gradually to a very narrow base I rigid and somewhat leathery, deep green on the upper surface, paler beneath with scattered hair-like scales, pinnate; pinnae up to about 40 on either side, some­ times opposite or sub-opposite at the base otherwise alternate throughout,. rather closely set (except toward the base) and often overlapping one another from below upwards, very 106 POLYSTICHUM shortly stalked, undivided, the margin serrate (except toward the base), the most prominent teeth having sharp spinous or bristle-like points and smaller blunt teeth on their sides or in between, the lowest and smallest pinnae deltoid to ovate­ deltoid, not or only indistinctly lobed at the base, the middle pinnae broadly lanceolate (convexly rounded on the side turned to the base of the frond and almost straight or concave on the other), very unequal at the base (broadly truncate with a well-marked lobe on the side turned toward the apex of the frond, cuneate on the other), the uppermost pinnae becoming relatively narrower and less markedly lobed at the base; venation N europteridian, the ultimate venules running toward but ending short of the tips of the serrations; rachis sharply channelled and with numerous narrow-lanceolate or subulate scales. Sori large, usually confined to the upper half of the frond, occupying the middle of the acroscopic fork of each secondary vein and forming a line on either side of the midrib of each pinna halfway between it and the margin, also on either side of the midrib of the basal lobe, and occasionally of the next one or two secondary veins. Indusium circular ~ peltate, its margin irregularly crenate or toothed. P. aculeatum vaT. cambricum (p. 105) is sometimes mis­ taken for this species. Reek fissures on the higher mountains; very rare. First recorded, 1690; Lhwyd in Ray, Syn., ed. 1, 27. 'Clogwyn y Garnedh y Crib G6ch Trygvylchau [Caern.].' Distribution in Wales: Mer. and Caern. Recorded in error from Glam. and Mont., P. aculeatum var. cambricum having been mistaken for it. North Wales, northern England, the Scottish highlands and the west of Ireland. Circumpolar-alpine. Widely distributed in the northern regions and mountains of Europe, Asia Minor, northern Asia to the Himalayas. Greenland and North America to Colorado in the west and Wisconsin and Nova Scotia in the east. Specimens in Herbarium,-Caern. : Snowdon, H,W.; above Bethesda, C.W., 1876; Cwm Glas, H.A,H" 1924.

Tribe 2. THELYPTERIDEAE Rhizome and fronds as a rule sparsely scaly, rachis and veins (at least above) with simple or branched hairs; leaf-stalk with 1-2 vascular bundles; veins free or united in pairs, reaching the margin. Sori mostly small, round (rarely elongated), with kidney-shaped indusium or none; sporangia often provided with bristly hairs. Plate 9. HOLLY YERN (Polystichum lonchitis) Reproduced from the cmgmving in Bolton's Pilices Britan'nicae (1785). 'Poli~ poclium lonchitis grows on the rocks of Glydur, near Llan berris, where I gathered the specimen here figured.' ~ l

Plate 10. Left: LIMESTONE POLYPODY (Gymnocarpium rouer!ianum) Middle: OAK FERK (G. dryopteris) Right: BEECH FERN (ThelyjJteris phegopteris) T. PALUSTRIS 107

Genus 19. THELYPTERIS Schmidel Rhizome erect or creeping, its small scales as a rule soft and hair like. Fronds of nearly all species lanceolate and bipinnatifid, narrowed below, rarely triangular, naked or with but few scales, but always pubescent with simple grey hairs, at least on the midribs above, the underside often with large,: sessile, red or yellow spherical glands; veins free, simple or the lowermost forked.-About 500 species, some few in northern regions. KEY TO SPECIES A \\"ith indusia; (roncl lanceolate in outline B Frond without glands, stalk practically as long as the blade 1. T. PALUSTRIS BB Frond glandular \wneath, stalk short 2. T. OREOPTERIS AA Without indusia; frond broadly triangular' in outline a. T. PHEGOPTERIS

I. THEL YPTERIS PALUSTRIS Schott (Dryopteris Thelypteris (L.) A. Gray Lastrea Thelypteris (L.) Bory) Marsh Fern (Fig. 59.) Rhizome long (up to lm.) and slender (0·Z5cm. or less), branched at intervals and creeping extel)sively just below the surface, bearing (at the apex and all the leaf buds only) a few small yellow to grey-brown lanceolate hair-pointed scales, which are very delicate and soon lost. Fronds' borne singly or sometimes in, small tufts at longer or 'shorter intervals on the rhizome, of two kinds, shorter sterile ones 15-60cm. (developed in Mayor early June), and taller, stouter and stiffer fertile ones 30--100cm. (developed a month later) ; stalk of sterile frond as long as .or somewhat shorter than the blade, that of fertile frond usually somewhat longer than its blade, both kinds brittle, black at the base, otherwise straw­ yellow to greenish, usually without scales or with a few ovate­ lanceolate scales below. Blade of sterile frond 7·5-37·5 X 5-lScm., of fertile frond 15-50 X 7·S-lOcm., both lanceolate in outline tapering at both ends (but the apex sometimes narrowing suddenly), soft, and membranous in texture, yellow- to bluish-green, without glands, pinnate; pinnae up to about 25 on either side, opposite or sub-opposite below and sometimes nearly to the apex, linear, lanceolate, shortly stalked to practically sessile, pinnatifid to almost pinnate; pinna-segments of the sterile fronds oblong-ovate obtuse or acute, those of the fertile fronds narrower and more acute (resembling the teeth of a comb) with the margins slightly 108 THELYPTERIS

wavy and reflexed over the sari, the lowest pair somet"imes much longer than the rest; venation Pecopteridian, the secon­ daries mostly forked and in the sterile frond the branches of the lowest secondaries forked again; rachises with scattered minute white hairs, those of the pinnae at first with a few very small scales, all becoming glabrous with age. Fertile fronds

Fig. 59. Marsh Fern, Thelypteris palustris. Left: sterile frond and fertile frond both attached to the rhizome (x i). Right: single segment of a median pinna from a fertile frond (X 5i). bearing sari to the extreme tip and often also to the base. Sorl small, rounded, situated just above the forks of the veins (on both branches when the secondaries are forked), forming two rows one on either side of the midrib of the segment and midway between it and the margin (apparently marginal owing to the reflexing of the actual margin), the under surface of the segment ultimately covered with an uninterrupted mass of sporangia. Indusium small: delicate, roundish kidney-shaped, deciduous, its margin irregularly toothed or torn and glandular.-To some extent resembles T. PALUSTRIS 109

T. Greapteris but may be distinguished by the creeping rhizome and scattered leaves, the long stalks, the relatively longer (not short and triangular) lower pinnae, the inrolled edges of the fertile segments and the absence of glands. . Fens and marshy thickets; rare. First recorded, 1796; Aikin in Withering, Arr. Brit. Plants, ed. 3, 3, 776. 'In a moist dell at the foot of Snowdon near Llanberris. ' Distribution in Wales: Mon., Glam., Rad., Carm., Pemb., Caem., Flint., Angl. Scattered throughout England and Wales; in Scotland only in mid-Perthshire and Foriarshire; in Ireland chiefly in the sou tb-west. Cosmopolitan. Throughout almost the whole of Europe but becom­ ing less frequent in the Mediterranean ,region, Algeria. Transcaucasus, Temperate Asia to China ·and Japan and the Himalaya. Southern India. New Zealand. Tropical Africa. South Africa. Eastern North America from New BrunswicK to Manitoba, south to Florida and Texas. Specimens in Herbarium.-Mon.: Pont-y-spig, A.L., 1874; Shire­ newton, W.A.S., 1897. Glam.: Singleton, c'H.B., 1849. Pemb.: Penally Ma~sh, F.L.R., 1942. AngI.: nr. Beanmaris,' C.W., 18?6; Llyn Llwydlarth, J .E.G., 1884; Llyn Penrhyn, J .E.G., 18QO.

2. THELYPTERIS OREOPTERIS (Eh rh.) C.Chr. (Dryapteris Greapteris. (Ehrh.) Maxon Lastrea Greapteris (Ehrh.) Bory) Mountain Fern (Fig. 60.) Stock about 10cm. long, stout, branched, sometimes caespitose, ascending, the older parts clothed with,the bases of dead fronds, the younger parts with brown; ovate to lanceolate, acuminate scales. Fronds tufted, 30-90cm. or more, fragrant when bruised, with a balsam-like odour; stalk short, about t as long as blade, rather sparsely clad with pale-brown ovate or ovate-lanceolate, acuminate scales. Blade 25-75 x 8-25crn. lanceolate in outline, tapering at both ends, often bright yellowish-green, pinnate; pinnae about 20-30 on either side, opposite or SUb-opposite at the base, becoming alteniate toward the apex, linear-lanceolate. (except the lowest pairs which are very short and triangular) with numerous sessile golden'-yellow glands beneath, sessile, pinnatifid; pinna-segments oblong, equal-sided, obtuse or slightly sickle-shaped, acute, with the apex incurved toward. that of the pinna, their margins slightly and irregularly crenate, the lowest acroscopic segments the longest and 110 THEL YPTERIS curved toward the main rachis; venation Pecopteridian, the lower secondaries forked, the remainder unbranched, ultimate venules not quite reaching the margin; rachises and midribs with fine white glandular hairs intermixed (especially in the

Fig. ,GO. Mountain Fern (Thetypteris Oreopteris). Left: single frond from an average-sized plant (x i). Right: single sl;!gment of a median pinna (X 5,1. lower part) with a few scales and jointed hairs. Sori small, borne on the vein endings (on both branches when the second­ aries are forked) forming a row near the margin of the segment. Indusinm small, irregular in shape, dentate along the margin, -often imperfect, always disappearing early, and sometimes absent altogether.-For comparison with T. patustris see under that species. T. OREOPTERIS III

Stream sides and dam~ woods; common in mountainous districts. First recorded, 1726; Dillenius, MS. diary of his journey in Wales. (Druce and Vines, The Ditlenian Herbaria, xlix. 1907.) Cader Idris. Recorded from every county in Wales. Throughout the British Isles. Circumpolar. Europe from southern Lapland and western Russia to northern Spain. Central Italy and the Caucasus. Madeira. North­ eastern Asia Minor. Japan. Western ::\orth America from Alaska to \Vashington.

3. THELYPTERIS PHEGOPTERIS (L.) Slosson (Polypodium Phegopteris L. Phegopteris polypodioides Fee) Beech Fern (PI. 10, Figs. 61, 62.) Rhizome creeping, slender, up to 20cm. X 1-2mm., sparingly . branched and rooted, blackish-brown, clothed when young

Fig, 61. Beech Fern (Thelypteris Phegopteris). Third pinna (rather larger than natural size).

with minute whitish woolly hairs and scattered gblden-brown ovate to oblong scales. Fronds 20-40cm., arising singly at irregular intervals from the rhizome; stalk as long or twice as long as the blade, brittle, dark brown at the base, otherwise greenish, usually clothed (at least in the upper half) with minute reflexed hairs, the base beset with lanceolate pale­ brown scales, the rest of the stalk with or without scaltered scales. Blade 10-20 X 8-IScm." triangular or triangular­ ~vate· in outline, acute or acuminate, dull pale green, thin, 112 THELYPTERIS pinnate; pinnae about 20 or more on either side, opposite or sub-opposite at the base, usually becoming alternate,all fringed with hairs and with scaltered hairs on both surfaces especially on the mid­ ribs, deeply pinnatifid, the lowest ·pair rather distant and deflected downwards away from the rest, lanceolate, acute, attached by the midrib only, the next pairs horizontal, Fig. 62. Beech Fern (Thelypter-is Phegop­ lin e ar-l an ce 61 ate, teris). Single segment of a median acute or obtuse, attach­ pinna (x St). ed by a broad leafy base, the rest directed more or less upward, oblong, obtuse, similarly· attached, running together toward the apex; pinna-segments oblong, obtuse, entire or slightly (rarely strongly) crenate; venation Pecopteridian, the secondary veins simple or forked; rachis with acuminate scales and scattered hairs. Sori circular, situated close to the margins of the segments mostly on the secondary veins or, where these aTe forked, on the "acroscopic or rarely on both branches. Indusium absent. Moist shady places: rocky woods, ravines, strearnsides, and by waterfalls; locally frequent. First recorded, 1726; Herb. Dillenius (Druce and Vines, The Dillen.ian Herbaria, 48, 1907), 'Hysvae in a cave [Caern.]' and 'Nascitur capiase in monte Snodon [Snowdon] Llan­ berys saxosis lods subudis.' Recorded from all counties in Wales except Pemb. and Angl. Throughout Scotland and chiefly in the mountain districts of England, Wales and Ireland. Circumpolar. Throughout Europe from Iceland and northern Scandinavia to the Pyrenees. Corsica. Northern Italy and Jugo­ Slavia. Caucasus, North-eastern Asia Minor. Northern Asia to Himalaya and Japan. Greenland, Arctic and Temperate North America, southwards to Washington and Virginia. Specimens in Herbarium.-Mon.--; nr. Mamhilad, T.H.T., 1859; Tintern, W.A.S., 1892; Kilgwrrwg, W.A.S., 1908; Penallt, S.G.C., 1924; Taren yr Esgob, S.G.C., 1941. Glam.: Melincourt Falls, T.B.F., 1852; Craig y llyn, J .A.W., 1923; Padell y bwlch, A.E.W., 1938. Brec.: below Neuadd Reservoir, G.R.W., 1907; Ystradfellte, B.A.H., 1925; nr. Scwd Einon Gain, A.E.W., 1925; nr. Abergwesyn, A.E.W., 1929; nr. YsgwdHenrhyd, J.A.W., 1944. Carm.:Llandovery, H.H.K., 1907. Card.: Devil's Bridge, W.H.P., 1848; Parson's Bridge, Aberyst",:,"yth, J.H.S., 1922. Mont.: LIangadfan, l.A.W .. , T. PHEGOPTERIS 113

1940; Llyfnant Valley, l.A,W., 1941. Mer.: nr. Cwrt and Pant­ perthog, ].A.W., 1940; Pistil y Caen, Cynfal Glen and Tabor, nr. Brithdir, J .A.W., 1941. Caern.: -Bettws y Coed, 1860 (collector un­ known); nr. Twll-dft, C.W., 1876; Nant Ffrancon, ] .E.G., 1893; nr.· Beddgelert, C,Wa., 1918; Cwm Glas, H.A.H., 1924; Dulyn Glen, A.W.,1928. Denb.: nr. Llanwrst, 'VIT,H.R., 1864; above the Wrexham and 1\uthin road, C:Wa., 1917. Genus 20. GYMNOCARPIUM Newm. (em. Chlng)* Rhizome widely creeping, slender. Fronds distaJlt; stalk long, erect, sparsely scaly at the base only; blade deltoid or pentagonal, prominently jointed to the stalk and bent back, either simple, deeply pinnatifid or compound, bi- or at the base even tri-pinnate, the lowest pair of pinnae much the largest and the most divided; veins forked, free. Sori circular to ovate-oblong, without indusia.-5 species; Europe, North America and south-eastern Asia. KEY TO SPECIES Frond quite glabrous 1. G. DRYOPTERIS Frond glandular 2. G. ROBERTIANUM

I. GYMNOCARPIUM DRYOPTERIS (L.) Newm. (Phegopteris Dryopteris (L.) Fee Polypod.ium Dryopteris L.) Oak Fern (PI. 10, Fig. 63.) Rhizome creeping, slender, up to 20cm. X 1-2mm., sparingly branched, and with few roots, black, glossy, the younger parts only clothed with pale brown ovate scales. Fronds 1O~40cm., arising singly at irregular intervals from the rhizome, when very young resembling Jlittle balls on wires; stalk It-3 times as long as the blade, siender, brittle, blackish­ brown at the extreme base, otherwise straw-coloured, with a few ovate-lanceolate pale brown scales at the base, otherwise glabrous. ' Blade 5-15 X 6-17cm., bent back into a horizontal position at right-angles. to the vertical stalk, broadly trianguiar, bright yellowish-green, thin, glabrous, tripinnate, changing rapidly upward to simply pinnatifid; pinnae about 6 distinct pairs, opposite throughout, the lowest pair of pinnae distant from the others, long stalked (their stalks conspicuously jointed to the main rachis) and much the largest (often almost as large as the rest of the blade) unequally ovate in outline (wider on the side away from the apex of the frond, the lowest

* Ching, R.C. On the nomenclature and systematic position of Polypodium Dryopteris L. and related species. Contr. Bioi. Lab. Se. Soc. China, IX, 30-43. 1933. 114 GYMNOCARPIUM pinnule on this side being as large- as the pinnae of the third pair), acute or obtuse, bipinnate; the second pair of pinnae stalked or sessile, attached by a knotty joint, oblong to oblong-lanceolate in outline, pinnate; the remaining distinct pinnae sessile and becoming decurrent, all acute or obtuse, pinnate becoming pinnatifid; pinnnles of first pair of pinnae pinnate, their pinnulets ovate to oblong, entire or crenate­ margined or pinnately toothed, rounded at the apex; pinnules of the upper pinnae resembling the lowest pinnulets of the first pair; venation Pecopteridian, the secondary veins of the segments simple or forked; rachis glabrous. Sori circular

Fig. 63. Oak Fern (Gymnocarpium Dryopteris) , Third basiscopic pi~nule of second pinna (X 5t)· or the lowest ones somewhat elongated, situated fairly close to the margin, on the secondary veins, or, if these are forked, 011 the acroscopic branch or on both, the sporangia sometimes running together to form an apparently continuous band. Indusium absent. Rocky woods, shaded rocky banks of streams, by waterfalls and-on screes; locally frequent. First recorded, 1662; Ray, Itinerary HI (Memorials ed. E. Lankester, 179, 1846). 'Near Tintern.' Recorded from every county in Wales. Throughout Scotland and Wales; in -England chiefly in the mount­ ainous districts; in Ireland Tare and local. Circumpolar, Throughout northern and central Europe, southwards to the mountains of the Mediterranean region. Asia Minor. Northern Asia to China and Japan. North-western Himalaya, Greenland, Arctic and Temperate North America, southwards to Arizona, Kansas and Virginia. Specimens in Herbarium.-:Mon.: ur. Mamhilad, T.R.T., 1857; Llandogo Falls, W.A.S., 1890; Taren yr Esgob, S.G,C., 1941. Brec.: Cwm Taf-fechan, G.R.W., 1907; Craig Cerig-gleisiad, A.E.W., 1926; nr. Erwood, A.E.W., 1929; Cocd Dinas, Grwyne Valley, S.G,C., 1944. Rad.: Elan Valley, S.G.C., 1946. Carm.: Cwm Gwern-fclen, H.H.K., 1907. Card.: Parson's Bridge, Aberystwyth, J.H.S., 1922. Mer.: Torrent Glen, Dolgelley, J.A.W., 1941. Caern.: Twll-dft, C.W., 1877; Cwm Idwal, H.A.H., 1924. Denb.: Pant y Glyn Diffws, J .A.Whe., 1942. G. ROBERTIANUM 115

2. GYMNOCARPIUM ROBERTIANUM (Hoffm.) Newm. (Phegopteris Robertiana (Hoffm.) A. Br. Polypodium calcareum Srn.) Limestone Polypody (PI. '10, Fig. 64.) Rhizome creeping, relatively stout, up to 20cm. X 3·5mm., sparingly branched and with a few roots, the younger parts with lanceolate brown scales and golden-brown woolly hairs. Fronds 15-55cm., arising singly at irregular intervals from the rhizome; stallr 1 ~-2 times as long as the blade, soft and sappy when young becoming firm, dark brown and with a few brown lanceolate scales at the extreme base, straw coloured and rarely with scattered scales above, glandular when young.

Fig. 64, Limestone Polypody (Gymnocarpium Robert~ ianum). Second acroscopic pinnule of second pinna (X 51), Blade 5-22 X 5-22cm" somewhat bent back at an angle to the vertical stalk, triangular in outline, dull green, glandular­ mealy, bi- or tri-pinnate changing rather rapidly upward to pinnatifid; pinnae opposite throughout, abolit 5-10 distinct pairs; the lowest pair of pinnae rather distant from the rest, stalked (their stalks stroligly jointed to the main rachis) and much the largest, linequally ovate-lanceolate in outline (wider on the side away from the frond-apex, the lowest pinnule on this side being as large as the pinnae of the fifth pair) acute to almost obtuse, simply pinnate or at the base bipinnate ; the second pair of pinnae usually stalked and well jointed to the rachis, broadly oblong-lanceolate, becoming linear, obtuse becoming rounded at the apex, pinnate or pinnatifid ; plnnliles of the first pair of pinnae pinnate or deeply pinnatifid ; ultimate segments oblong, rounded or truncate, and entire or crenate at the apex; venation Pecopteridian, the secondary venules sometimes forked ano. then only the acroscopic 116 GYMNOCARPIUM branch or rarely both branches fertile; rachis glandular. Sori small, round, forming a row on either side fairly near the margin. Indusium absent. Rocky woods and ledges, stony slopes and screes; frequent in limestone districts. First recorded, 1805; J. W. Griffith in Turner and Dillwyn, Bot. G,.ide, I, 96. Cwm Idwal, Caern. This is queried as a probable error. The fjrst certain record is in 1833; ·W. Christy, in Mag. Nat. Hist., VI, 52. 'A steep limestone declivity, on the left of the road just after leaving LJangollen, was completely covered with Polypodinm calcareum.' Distribntion in Wales: Mon., Glam., Brec., Rad., Carm., Mont., Caem., Denb.

Limestone districts of En~land and Wales. Scotland (mid- Perthshire only). Absent from Ireland. Circumpolar. Europe, from Iceland and northern Scandinavia, southwards to the Pyrenees, Corsica, Italy and the Balkan Peninsula. Afghanistan. Norther America from Labrador to Alaska southwards to New Brunswick and Iowa. Specimens in Herbarium.-Mon.: ur. Pontypool, T.H.T'J 1868; Highmeadow Woods, S.G.c., 1928; ur. Hadnock Quarries, S.G.C.,

1928; nr. Penallt, S.G,C' J 1935; Taren yr Esgob, A.KW., 1944. Glam.: Morlais Castle Hill, A.E.W., 1923; nL Caerphilly, A.R.W., 1924; nr. Padell y Bwlch, A.R.W., 1938. Brec.: Ystradfellte, E.N.M.T., 1921; between Maen Madoc and Ystradfellte, H.A.H., 1925; CraigMy~Ci1au, W.A.S., 1896, A.E.W. and H.A.H., 1926; Cantreff, nr. Merthyr, T.H.T., 1900. Carm.: Careg yr Ogof, H.I-LK., 1907. Caern.: between Bangor and Bethesda, C.W., 1876. Denb.:. nr. the Loggerhead,:;, J .D.M., 1930.

Subfamily 7. POLYPODIOIDEAE Sporangia borne on the nnder side of the leaf blade, super­ ficial or sunken, usually forming definite sori which are always without indusium and as a rule globose or oblong and borne on or near the ends of the veins if these are free, or variously placed in relation to the veins if· these are fused. Leaves generally jointed to the rhizome, the fertile ones sometimes distinct in form. Over 1,200 species, all bnt 4 or 5 Tropical or Sub-Tropical, mostly of small or medium size, often epiphytic. ,. * Brief notices of the Plants observed during a Tour through a part of North Wales and some of the adjoining Counties, 51-7. P. VULGARE 117

Genus 21. POL YPODIUM L. (em. C. Chr.) Rhizome creeping, fleshy, often glaucous and densely scaly. Fronds pinnatifid pr pinnate, rarely simple, all similar in form, non-scaly. Veins free in some few species (e.g. P. vulgare) but usually reticulate, a series of free-ending tertiary veinlets being enclosed within loops formed by other anastomosing veinlets (goniophlebioid venation). Sori terminal, nsnally in one row (less frequently 2-3 rows) on either side of the midrib.-About 50 species, 'mostly epiphytic, in Tropical and Sub-Tropical America, Asia and Polynesia; only a few free-veined species in the North Temperate zone. The solitary British species p, vulgare is described by H. Christ as having in all respects the appearance of a fern adapted to life in the Tropical r~in forest, 'an astounding phenomenon in the Cold Temperate ,zone,' ,

Fig. 65. Common Polypody (Polypodiu,m vulgare) , Single segment from an average-sized frond of an acutely-segmented form (x 2t).

POL YPODIUM VULGARE L. Common Po/ypody (Frontispiece, Fig. 65.) Rhizome horizontal, stout, up to 40cm. X 6-7mm., creeping on or beneath the surface, sparingly branched, somewhat flattened in cross-section, yellowish to dark brown with age, the younger parts thickly clothed with reddish-brown lanceo­ late peltately-attached hair-pointed scales. Fronds 5-45cm., arising at intervals and in two rows from .the upper side of the rhizome, winter-green, each jointed at the base to a more or less prominent boss which, capped by a scar, remains after the leaf has fallen; stalk from i to almost as long as blade, greenish glabrous and without scales. Blade 3-37 X 2·5-10cm., ovate or-ovate-lanceolate to linear-la-nceolate in" outline, acute to almost acuminate, dull green on the upper surface, paler beneath, firm in texture, pinnatifid; segments mostly alter­ nate, oblong, oblong-lanceolate or linear-lanceolate, obtuse or acute at the apex, their margins obscurely to deeply toothed, double toothed or lobed; venation Euptendian. Sari large, 118 POLYPODIUM round or oval, seated on the swollen ends of the lowest acroscopic branches of the secondary veins and forming a rowan either side of the midrib, usually midway between it and the margin of the segment. Hedgebanks, old walls, rocks and tree stumps, and epiphytic in the forks and along the branches of trees; common. First recorded, 1690; Ray, Syn., ed. 1,22. 'On a rock in a wood near Dennys Powys Castle [Dinas Powis Castle, Glam.J' This record is of the var. cambricum. Recorded from every county in Wales. Polypodium. vulgare is now known to comprise a number of sub-species which differ in the form of the frond and sorus, and also in their geographical distribution, but which have not yet been given names. (Manton, 1950.) Throughout the British Isles. Circumpolar. Chiefly in the North Temperate regions of both hemi­ spheres with extensions to South Africa and Kerguelen. Throughout Europe. North Africa and the Atlantic islands. Asia Minor and northern Asia to Tibet, China and Japan. Kerguelen. Ha".'aiian Islands. South Africa. North America from . Labrador and New­ foundland to Manitoba and southwards to Georgia, Alabama and Missouri.

Var. CAMBRICUM IL.) Lightfoot Welsh Po/ypody (Fig. 66.) Blade ovate or ovate­ lanceolate in outline, bi­ pinnatifid; segments nar­ rowed at the base, narrowly ovate Gr lanceolate in out­ line, pinnatifid, with oblong to linear lobes. Recorded from Glam., Pemb., Caern., Denb. Specimens in Herbarium.­ Glam.: or. Cardiff, H.J.R., 1908. Caern.: Conway Castle, C.W., 1876. De.b.: T.P.

Fig. 66. Welsh Polypody (Poly­ podium vulgare var. camb'licum) Ix t)· P. VULGARE 119

Var. SEMILAGERUM Link (Var. hibernicum Moore) Said to differ from var. cambricum in the upper segments being entire. Doubtfully distinct. Recorded from Mon., Pemb., Caern. Specimens in Herbarium.-Mon.;. Hafodyrynys, T.H,T., 1857. Caern.: Conway, J.E.G" 1893,

Order 2. Salviniale, Sporangia in spheri'cal sori (each surrounded by an indusium also spherical), some consisting of microsporangia each with numerous microspores, others of megasporangia each with one large megaspore, both kinds of sporangia without annulus. -Aquatic plants with horizontal branched stems, the leaves not circinate in the bud. Comprising two families, viz. Salviniaceae (only genus Salvinia) and Azollaceae.

Family AZOLLACEAE Characters as for the only genus.-6 species; Tropical and \Varm Temperate zones.

Genus 22. AZOLLA Lam. Very small floating aquatic plants, resembling in general appearance the leafy !iverworts. Stem much branched, bear­ ing roots and leaves. Leaves borne on the upper side of the stem in two rowS alternating right and left; each leaf deeply divided into two lobes, the upper one a green floating assimilat­ ing organ (containing also a chamber inhabited by threads of the blue-green alga Anabaena), the lower one thinner and submerged, the upper lobes of neighbouring leaves covering one another like tiles on a roof, so that the upper surface of the stem is hardly visible, the lower lobes only covering one another at their bases so that the under surface of the stem is ·more or less uncovered. Ro'ots numerous, solitary, arising from the under surface of the stem at the points of origin of the branches. Sari borne in one or two pairs on the lower lobe of the first leaf of a lateral branch, the entire gronp of 120 AZOLLA

sari being covered by a cowl-like flange of the npper lobe of the same leaf; each sorus wholly surrounded by its own indusium and, when mature, either globose, consisting of numerous microsporangia, ot smaller and acorn-shaped, con­ sisting of a single megasporangium, the two sari of a pair being of the same or assorted sexes. * Microsporangium long-stalked, containing a number of little clumps of rnicrospores, called massulae, each of which (in the only species found in Europe to-day) is beset with numerous barbed hairs (glochidia). The massulae are liberated by the decay of the indusium and the sporangium wall, and some become attached by the glochidia to the megaspores; fertilization follows.-6 species in the Tropical and ¥larm Temperate zones. Azolla and Salvinia were formerly included with the Marsileaceae under the heading' Hydropteridales (cf. 'p. 45). The Marsileaceae have now been placed riear their homosporous relative~ but the true position of the Salviniales remains doubtful. Their sporangia are developed in gradate succession, the indusium is basal, and the sari are situated on the ends of the leaf-segments: all three features pointing in the direction of Hymenophyllaceae, but connecting links are wanting.

AZOLLA F1L1CULOIDES Lam. Azolla (Fig. 67.) Plants. growing in dense tufted masses, l-Zcm. across, th ends of the sboots directed forward and outward and oftel protruding, not lying flat on the surface. Upper lobes of thl leaves about Imm. across, often reddish in colour, having a broad, distinct, clear margin and numerous one-celled hairs on the upper surface. Sori in pairs, either assorted or two megasori together, microsori up to 1·5mm., megasori up to Q·5mm. in diameter. Indusium of the microsorus translucent, so that the microsporangia are clearly visible under a lens. Stalks of the glochidia 75" long, not divided up into cells (i.e. non-septate). t

'" According to Christensen one sorus of a pair is a microsporangium sorus and -the other a megasporangium sarus. However, Goebel (quoted in Bower, Filicales, Hi, 261) figures two 'female' sori growing together, and we have repeatedly -observed this in A.-jiliculoides. t This character, which can only be observed under a "high power microscope, is" the clearest point of distinction from A. caroliniana Willd" another American species which is naturalized on the continent ·of Europe and has been said to occur also in England (ct Marsh, Journ. Bot., 52, 209, 1914)", though confirmation by means of 'fruiting' material seems to be entirely lacking. A. FILICULOIDES 121 Naturalized, and fruiting freely in ponds, drainage ditches and slowly-flowing streams. First recorded, 1922; J. D. Dean, Rep. B.E.C., 1922,6,755 (1923), Goldcliff, near Newport, Mon.

Fig. 67. Azolla (Azolla filiculoides). A, portion of plant; E, plant with sporangia; C, microsporangium; D, massula (with single glochidium more highly magnified); E, megaspor~ angium in vertical section. (From Butcher and' Strudwick, Further Illustra·tions of British Plants.)

In Wales found only in south Monmouthshire. Native of Tropical America. Occurs also in England and Ireland and on continent of Europe: France, Holland, Germany and Italy (natura~ lized in all), Found as a fossil in Interglacial deposits in Suffolk; also in Holland, Germany and Russia. Specimens in ·Herbarium.-Mon.: Goldcliff, J .D,D., R.L.S., 1922; Caerieon, H.A.H., 1927; St. Pierre Park, H.E.S., 1925; nr. Whitson, A.E.W., 1941. 122

APPENDIX Exotie famiUes referred to in the text, as illustrated by genera and species in cultivation. SCHIZAEACEAE. 4 genera, the commonest in cultivation being Anemia (stock usually upright, clothed with silky hairs; leaves pinnate, usually the lowest pair of pinnae only fertile) and Lygodium (rhizome horizontal clothed with ,hairs; leaves climbing, repeatedly dichotomous with continued apical growth). Sporangia: solitary; marginal at least in origin; protected in Schizaea by the leaf margin, in Lygodium by an indusium arising from the leaf surface; annulus a simple row of cells near the apex of the capsule. GLEICHENIACEAE. Gleichem'a (bas many species in cultivation): rhizome horizontal or ascending, branched and clothed with scales or hairs; leaves usually solitary, of straggling .habit, appearing to be dichotomou!,ly branched (as the result of non~development of the dormant apical bud and its supersession hy two lateral pinnae); sari superficial in a single rowan either side of the midrib; sporangia few. developing simultaneou~y; annulus complete, tr~nsverse.

DICKSONIACEAE (formerly included under Cyatheaceae). Mostly tree ferns (Dicksonia and Cibotium) only to be seen in botanic gardens: stems with hairs but no scales; leaves repeatedly pinnate; sori mar­ ginal, numerous; indusium 2-lipped; sporangia large, produced in basipetal sequence, with more or less oblique aIlnulus and lateral stomium.

CVATHEACEAE (excluding Dicksonieae). Mostly' tree ferns, with broad, chaffy scales often borne on persistent peg~like outgrowths; leaves spirally arranged in a crown, pinnate; sori superficial, gradate, borne on the veins; sporangia small, long-stalked; annulus oblique with definite stomium and lateral dehiscence; spores 64. The only important distinction between the three genera is in respect of the indusium: in Alsophila absent; in Hemitelia a basal scale; in Cyathea­ a cup completely covering the sorus when y~ung.

PLAGIOGYRIACEAE, Only genus Plagiogyria, species of which are rare in cultivation, Stem dwarf upright, sometimes with runners. Leaves in a cluster, fertile distinct from sterile. Sori superficial, mixed elongated along veins protected only by leaf margins. Sporangia long­ stalked with oblique annulus and lateral dehiscence. Spores 48. 123

LIST OF COLLECTORS

This is a complete list of the collectors whose specimens are referred • to in the text; their names are arranged alphabetically in the order of their first. initials.

A.A.D. A. A. Dallman ].D.D. J. Davy Dean A.E.W. A. E. vVade .I.D.M. J. D. Massey A.],W. A. J. Wilmott J .E.A. J. E. Arnett A.L. A. Ley J.E.G. J. E. Griffith A.W. A. Wilson J.F.J. J. F. Jones A.We. A. Webster J .F.P. J. F. Pickard B. Baxter (J. ?) J .G. ] ohn Grimes B,A.W. B. A. Williams J .H. John Hardy C,B. Charles Bailey J .H.A.S. J. H. A. Steuart e.c. Charles-Conway 'j.H.S. Dr. J. H. Salter CC.B. C. C. Babington J .L.C. J. L. Crowther C.M.L. Mrs. C. M. Le Lacheur J .L.M. J. L. Monk C.H.B. C. H. Buckland ].L.W. Dr. J. Lloyd WilHams C.V.I3.M. C. V. B. Marquand J.W.G.G. J. W. G. Gutch C,W. j. T. Creswick Williams J.W.W. J. W. White C. Wa. Charles Waterfall J .R.H. J. R. H'olmes C.W.B. Mrs. C. W. Begg K.M.G. Miss K. M. Green D.A.]. D. A. Janes L.N. Miss L. North E.e.H. Miss"E. C, Howells M.B. Miss M. Brown E.L.D. E. Lowder Downing M.H. Miss M. Hall KM.T. l\1iss E. Mary Thomas M.H.N. Morley H. Neale E,N.M.T. Dr, E. N. Miles Thomas M.L. M. L1~wellyn E.P, E. Pattison M.S. Initials on a sheet in E,V. Miss E. Vachell Herb. Horwood E,Y. Edward Young P.G.M.R. Rev. P. G. M. Rhodes F.H.B.M. Miss F. H. B. Marsh P.W.R. Dr. P. W. Richards F.L.K Mrs. F. L. Rees R. Mrs. Rippon F,r.]. F. TaHaurd lanes RL. R. Lewis G.F. George Francis R.L.S. R. L. Smith G.H.B. Dr. G. H. Bryan RS.H. R. S. Huttxm G.H.G. G. H. Gale S.G.C. S. G. Charles G.R.W. G. R. Willan S.P.R. S. P. Rowlands H.A.B. H. A. Hyde S.R. S. Rowland H.E.S. H. Edgar Salmon T.B.F. T. B. Flower H.H. H. Harries T.H.T. T. H. Thomas H.H..K. H. H. I{nig-ht T.P. Thomas Pritchard H.I.]. H. 1. lames V.M.P. Miss V. M. Peel H.J.R. Rev. H. J. Riddelsdell W.A.S, Dr. W. A. Shoalbred H. S. H. Searle W.C.B. W. C. Bartan H.W. Hamlet Wilson W.H.P. Rev. W. H. Fainter J.A.W. J. A. Webb W.H.R. W. H. Rylands J.A.Wh. J. A. Wheldon W.!. Wm. Ingham J .A.Whe. J. A. Whellan W.RR. Lt.MCal. W. R. Roberts J.B.W. Dr. J. B. Wood W.W. William Wilson J .C.E. Mrs. J. C.Ellis 125

BIBLIOGRAPHY

(a) GENERAL. 1. Bower, F. 0., The Ferns (Filicales). 3 vols. Cambridge, 1923-28. 2. Bower, F. 0., Primitive Land Plants. London, 1935. 3, Christensen, C., Filicinae; in Manual of Pteridology (ed. Fr. Vef M doom). The Hague, 1938. 4. EngIer, E., and Gilg, E., Syllabus dey Pjlanzen!amilien. Ed. 8, Berlin, 1919. 5, Verdoorn, Fr. (ed.). Manual of Pteridology. The Hag-ue, 1938. 6. Manton, I., Problem~ of Cytology and Evolution in the Pteridophytes. Cambridge, 1950.

(b) DESCRIPTIVE, 7. Christ, H., Die Farnkrauter dey Erde, jena, 1897. 8. Hooker, W. j., Species Filicum. 5 vols. London, 1846-64. 9. Hooker, W. -J.> The British Ferns. London, 1861. 10. johnson, C., and Sowerby, J.E., The Ferns of Great Britain.' London, 1859. 11. Lowe, E. J" Ferns: British and Exotic. 8 vols. London, 1867. 12. Lowe, E. J., Our Native Ferns. 2 vols. London, 1867-69. 13. Luerssen, C., Die Farnpflanzen oder Gefassb1'jndelkryptogamen (Pteridophyta). {Rabenhorst, Kryptogamen~Flora, 2 aufi., Vol. 3.} Leipzig, 1884-89. 14. Moore, T., The Ferns of Great Britain and Ireland (Natttre~printed bY,Henry Bradbury). Folio. London, 1855. 15, Moore, T., The Nature Printed British Ferns. 2 vols. London, 1859-60. 16. Ncwman, E., A History of British Ferns and Allied Plants. Eel. 1, London, 1840; Ed. 2, London, 1844. 17. Newman, E., A History of British Ferns. London, 1854. 18. Sowerby, J. and j. E., English Botany. Eel. 3 by J. T. Boswell Syrne. London, 1902.

(c) NOMENCI.ATURE, 19, Christensen, C., Index Filicum, Hafniae, 1906. Supplements I-Ill, 1913-34. 20. Druce, G. c., British Plant List. Arbroath, 1928. 21. [Hanbury, F. j., ed,], The London Catalogue of British Plants. Ed. 11. London, 1925 ..

(d) DISTRIBUTION, (i) General 22. Christ, H., Die Farnkrauter der Erde. jena, 1897. 23. Christ, H., Die Geographie der Farne. Jena, 1910. 24. Winkler, H., Geographie in Manual of Fteridology (ed. Fr. Ver­ doom.) The Hague, 1938. (ii) British, especially Welsh. 25. Barker, T. W ., Handbook to the Natural 'History of Carmartltenshire. Carmarthen, n.d. [1905J. 26. Bennett, A., Supplement to Topographical Botany, ed. 2. London, 1906. 27. Bennett, A., Salmon, C. E., and Mathews, J. R., Second supple­ roent to Watson's Topographical Botany. London, 1930. 126 BIBLIOGRAPHY

28. Clark. J. H., The Flora of Monmouthshire. Usk, n,d. [1868J. 29. Davies, Hugh, Welsh Botanology. London, 1813. 30 .. Dillwyn, L. W" Materials jar a Fauna and Flora of Swansea and the neighbo1Whood. Swansea, 1848. 31. Druce, 9-. C., The Comital Flora a/the British Isles. Arbroath, 1932. 32. F[alconerJ, R. W., Contributions towards a Catalogue oJ Plants indigenous to the neighbourhood of TenbY. London, 1848. 33. Griffith, j. E., The Floraoj Anglesey and Carnarvonshire. Bangor, n.d. [1895J. 3{ Hamilton, S., The Flora of Monmouthskire. Newport,. 1909. 35. Riddelsdell, H. j., A Flora of Glamorgansh-ire. London, 1907. 36. Salter, J. H" The Flowering Plants and FeYns of Cardiganshire. Cardiff, 1935. . 37 . Shoolbred, W. A" The Flora of Chepstow. London, 1920. . 38. Starrie, J., The .Flora of Ca-Ydiff. Cardiff, 1886, 39. Trow, A. H. (Editor), The .Flora of Glamorgan, Cardiff, 1911. 40. Turner, D., a'nd Dillwyn, L. W., The Botanist's Guide. 2 vols. London, 1805. 41. Vachcll, E., 'Flowering Plants and Ferns' in Glamorgan County History, Vol. I, Natural History. Ed. W. Tattersall. Cardiff, 1936. . 42. Watsan, H. ,C., Topographical Botany. Ed. 2. London, 1883. For supplements see under Bennett. 43. Young, Edward, The .Ferns of Wales. Neath, 1856. Information has also been obtained froin the following periodicals: Phytologist, Annals and Magazine of Natural History, Journal of Botany, Science Gossip, Reports of the Watson Botanical Exchange Club, Reports of the Botanical E;l;change Club of the British Isles.

(e) HISTORICAL. 44. Bolton, J., Filices Britannicae. P~. 1, Leeds, 1785; ? Pt. 2, Huddersfield, 1790. 45. Druce, G. C., and Vines, S. H., The Dillenian Herbaria. Oxford, 1907. 46. ·Gibson, Camden's Britannia. London, 1695. 47. Hooker, W. J., The British Flora. Ed. 1. London, 1830. 48. Johnson, T., Mercurii Botan'ici pars altera. London, 1641. 49. Lankester, E. (ed.),_ Memorials of John Ray. London, 1846. 50. Moore, J., A Handbook of British Ferns. Ed.1. London, 1848. 51. Parkinson, J., Theatrum botanicum. London, 1640. 52. Petiver, J'J Graminorum ... et britannicorum concordia. London, 1716. 53. Ray, J., Catalogus Plantarum Angliae. London, 1670. 54. Ray, J., Synopsis stirpium britannicarum. Ed. 1, London, 1690; Ed. 2, London, 1696; Ed. 3, London, 1724. 55. Sales bury, William, Llysieulyjr Meddyginiaethol (ed. E. Stanton Roberts). Liverpool, 1916. 56. Turner, Dawson, Extracts from the literarv and scientific corres~ pondence of Richard Richardson, M.D., F.R.S. Yarmouth, 1835. 57. Withering, W., Arrangement oJ British Plants. Ed. 2, London, 1792, Ed. 3,1796; Ed. 4,1801. 127

INDEX AND GLOSSARY This glossary contains all the technical terms employed in the main text: those which are used only in the Introduction are not included. The definitions given apply to the words as used in this book only; for a more complete treatment of botanical terminology on etymological lines' reference should be made to B. D. Jackson's Glossary of Botanic Terms. The Latin names of the ferns (genera and species) described in this book are printed below either in heavy type (names in current use and regarded as valid) or in italics (alternative names, i.e. synonyms). The names of families are printed in small capitals. All other Latin names are printed in ordinary type. Page 'Page acroscopic (side of pinna ; pin~ A. marlnum 67 nule): facing toward the A.obovatum 70 apex of the frond; (side· of A. Ruta~muraria 73 pinnule; pinnulet) : facing A. septentrionale 76 toward apex of pinna A. Trichomanes 68 acuminate: having a gradu- A. viride 69 ally diminishing point Asplenophyllitis 64 a9ute: sharp .. pointcd Athyrieae 79 adder's tongue 40 Athyrinm 79 Adianteae 59 A. alpestre 82 Adiantum 59 A. Filix~femina 80 A. Capillus~Veneris 60 A. flexile 82 adpressed :. lying flat for the axis, axial: the central por­ whole of its length tion of a plant or organ to alternate (segments): arising which the outer portions in succession on opposite are attached, as leaves to sides of the rachis each one stem or pinnae to rachis at a higher level than the Azollaceae 119 last azolla , , 120 anastomosis: one vein unit­ AzolIa '119 ing with another, the con­ A. filiculoides 120 nection forming part of a network annulus: group of thick­ walled cells (usually in the basipetal: arising succes­ shape of a ring) which sivelv from- above down­ brings about the bursting wards of the sporangium basiscopic (side of pinna; pin­ Anogramma 59 nule): facing toward base A. leptophyll. 59 of frond; (side of pinnule : apex: tip, summit pinnulet): facing toward Asplcnieae 64 base of pinna Asplenioideae 63 beech fern 111 Asplenium 66 bifid: two-cleft. A. Adiantum~nigrum 72 bipinnate (blade): pinnate X A. Br.ynll 75 with pinnate pinnae A. fontanum '71 bipinnatifid (blade) : pinnati­ A, gerrnanicum 75 fid with primary divisions A, lanceolatum 70 again pinnatifid 128 INDEX AND GLOSSARY

Page Page bipolar: occurring in the cuneate: wedgeMshaped North Temperate and/or Cystopterls . . . . 82 Arctic and also in the South C. Dlckieana 84 Temperate and/or Antarc~ C. fragilis .. 82 tic zones, but not in the C. Montana 84 Tropics C. regia B4 bladder fern, brittle 82 Blechnoideae 61 deciduous: falling in season B1echnum 62 decumbent: with the base B. spicant .. 62 reclining but the summit Botrychium .. 38 ascending B. Lunaria 38 decurrent (base of leaf seg­ bracken fern . . 55 ment): running down the bristle fern 53 axis below the point of buckler fern{s) 90 attachment broad .. 94 defiexed: bent downwards crested I 94 dehiscence (of sporangium) : hay-scented 99 bursting narrow 97 deltoid: shaped like an equi­ rigid 93 lateral triangle dentate (margin): toothed, caespitose: growing in tufts especially with salient teeth Ceteracb 77 directed forward C. officinarum 78 dichotomous: forked ciliate (margin) : fringed with Dryopterideae 90 hairs Dryopteridoideae 89 circinate (fronds in the bud) : Dryopteris 90 crozier-like D. abbreviata 92 circumpolar : occurring either D. aemula .. 99 throughout the North Tem­ . D. aristata 94 perate and Arctic zones or D, Borreri 92 - throughout the South Tem­ D. cristata . . 94 perate and Antarctic :lOnes D. dUatata . . 94 coenosorus : apparently single D. Filix-mas 91 sorus formed by several sari D. Oreopteris 109 having grown together D. remota 100 commissure: vein linking tOM D. spinuiosa 97 gether two other veins of a D. Thelypteris 107 higher degree of importance D. uliginosa 100 .cordate: heartMshaped D. Villarsii 93 cosmopolitan: occurring entire: undivided, without throughou t the world teeth crenate (margin): with epiphytic: growing upon but rounded teeth or notches; not parasitic on other plants scalloped equal: symmetrical crenatoMpinnatifid : shallowly pinnatifid with the segM fertile: b~aring sporangia ments rounded at their Filicales 42 apices Filicinae 37 crenate...,sinuate (margin) : Filkes Eusporangiatae 37 waved, with the projecM Filices Leptosporangiatae 42 Hons resembling large conM filmy fern(s) .. 48, 49 vex teeth Tunbridge .. 50 Cryptogramme 57 Wilson's 52 C. crisps 58 fimbriate (indusium) : fringed Cryptogrammeae 57 with long slender processes INDEX AND GLOSSARY 129

Page Page free (veins): not joined up, L. spinulosa 97 ending blindly L. l'helypteris 107 frond: the fern leaf including latticed (hair or scale) : cross­ the stalk barred lax: loose, distant glabrous: devoid of hairs or linear: narrow, several times glands longer than wide gland: organ of secretion, lobe: a shallow segment often capping a hair glandular: possessing glands maidenhair fern 60 glaucous: covered with a male fern 91 bloom as a plum or a cahw dwarf 92 bage leaf golden-scaled 92 globose: nearly spherical marginal: situated on the gradate (sorus): developing margin its sporangia in basipetal marsh fern 107 succession MARSILEACEAE 45 Gymnocarpium 113 median: placed midway or G. Dryopteris 113 nearly G. Robertlanum 115 megasporangiuro: sporan­ Gymnogrammeoideae 57 gium containing mega­ spores hard fern 62 megaspore: the latger kind hart's-tongue fern 64 of spore in the heterospor­ heterosporous: having spores ous ferns of two kinds megasorus: sorns g~ving rise holly fern 105 to megasporangia homosporous: having spores microsporangium : sporan- of one kind only gium containing micro­ HYMENOPHYLLACEAE 48 spores Hymenophyllum 49 microspore: the smaller kind H. pelt.turn 52 of spore in the heterospor­ H. tunbrigense 50 ous ferns incurved: turned' inwards microsorus: sorns giving rise indusium: the membrane to microsporangia covering the sarus when midrib: distinct central vein young of a pinnately veined simple .inferior (indusium): situated blade or of a segment of a below the sorus divided blade mixed (sorns): developing its Killarney fern 53 sporangia promiscuously, not simultaneously or in lacerated: torn or irregularly sequence cleft moonwort 38 lady fern 80 mountain fern 109 lanceolate: narrow, tapering mucronate: ending in a short to the apex but not neces w and straight point sarHy narrowed at the base Lastrea aemula 99 oak fern 113 L. cristata 94 oblanceolate : lanceolate with L. dilatata .. 94 the widest part above the L. Filix-mas 91 middle L. F oenisecii 99 oblique (annulus) : in a plane L. Oreopteris 109 inclined at an angle to the L. propinqua 92 long axis . L. pseudo-rnas 92 oblong: longer than broad with L. rigida 93 more or less parallel sides 130 INDEX AND GLOSSARY

Page Page obovate, obovoid: inversely pinnules: the divisions of a ovate with the widest part pinna when quite distinct; above the middle secondary pinnae obtuse: blunt at the apex pinnulets: the divisions of a OPHIOGLOSSACEAE 37 pinnule when quite dis­ Ophioglossales 37 tinct; tertiary pinnae Ophloglossum 40 POLYPODIACEAE 54 o. lusitanicum 42 PoJypodioideae 116 O. vulgatum 40 Polypodlum 117 opposite (segments): arising P. calcareum 115 in succession In pairs on P. Dryopteris 113 opposite sides of the rachis P. Phegopteris 111 orbicular: with a circular P. vulgare .. 117 outline ~ polypody, common 117 Osmunda 43 polypody, limestone 115 O. regaUs 44 polypody, Welsh 118 OSMUNDACEAE 42 Polystlchum lOO ovate: egg:.-shaped in outline P. aculeatum 103 and broadest toward the P. angulare 101 base P.lobalum 103 ovate-acuminate: ovate in P. Lonchitis 105 outline with the apex drawn P. setiferum t01 out into a gradually dimi­ primary (segments): of the nishing point first order ovate-deltoid: broadly ovate prothallus ; the gametophytic with the greatest width very or sexual generation of a near the base fern arising from the ger­ ovate·lanccolate: ovate in mination of a spore shape but two or three pterldium 55 times as long as broad P. aqullinum 55 ovate~oblong : ovate, with the Pteridoideae .. 55 sides nelitrly parallel Pteris aquilina 55 pubescent: clothed with soft palmate (blade) c:ompound hairs or down with the divisions all run­ ning toward and attached directly to the leaf stalk parsley fern 58 peltatp-: shield-like, ronudish rachis: the axis of a com­ with a more or less central pound frond excluding the attachment stalk Phegopteris Dryopteris 113 receptacle: the part of the P. polypodioides 111 frond (usually raised above P. Robertiana 115 the general surface) to Phyll!tis 64 which the sorus is affixed P. Scolopendrium 64 rccurved: curved backwards Pilularia 46 reflexed: bent backwards or P. glo bulifera 46 downwards pillwort 46 reniform; kidney~shaped pinna': primary division of reticulate (veins); forming a pinnate blade network pinnate: branched or divided rhizome: stem growing more like a feather with distinct or less horizontally on or leaflets borne to right and under the surface and left of a central axis (the usually having distinct rachIs) upper and under sides INDEX AND GLOSSARY 131

Page Page royal fern 44 stoma (pI. stomata) : breath- rusty-back fern 78 ing pore in the epidermis of the blade or stalk stomium: point at which SalviniaJes 119 sporangium bursts open to Scolopendrtum 11ulgare 64 liberate spores secondary (segments) : of the sub- (prefix): approaching, second order nearly, rather less than seg.ment: any division into subulate: awl-shaped which a leaf· blade is cleft superficial (sari): on the sur­ whether completely to the face (in contradistinction to midrib or not marginal) serrate: toothed like a saw superior (indusium) : situated sessile: stalkless above the sorus shield fern, hard 103 shield fern, soft 101 ternate (blade) : divided into simple (leaf·blade): undivi- three more or less equal ded; (sorus): developing divisions all its spora.ngia simultan­ terrestrial: growing on the eously ground sinuate: wavy tertiary (segments): of the sorus (pI. .sori): a cluster of third order sporangIa Thelypterideae 106 spike: a narrow form of frue­ Thelypterl, 107 tification in which the spor­ T. Oreopteris 109 angia are sessile T. palustris 107 spinulose: with small spines T. Phegopterl, 111 Of spinules triangular - ovate (outline): spinulose-mucronate: tipped ovate tending to triangular with a spine-like point Trichomanes .. 53 spleenwort(s) 66 T. radicims 53 alternate-leaved 75 T. speciosum 53 black 72 trifid: three-cleft forked 76 truncate: terminating ab­ green 69 ruptly as if cut off square lanceolate 70 maidenhair 68 ultimate (segments) : the final sea .. 67 divisions of a compound smooth rock 71 blade spore: minute seed-like body unequal: asymmetrical which on germination gives rise to the prothallus venation: arrangement of sporangium (pI. ~ia) : capsule the veins of a blade or seg­ containing spores ment sporocarp (Marsileaceae only): vernation: the order of un­ a globose body containing folding from leaf buds sporangia wall-rue 73 sterile: barren, not bearing 85 sporangia Woodsla stipules: paired leafy growths W. alpina 87 at the base of the frond W. ilvensis 85 stock:. short underground woodsia, alpine 87 stem woodsia, oblong 85 stolon: runner or basal Woodsioideae 85 branch which roots inde­ Xerophilous: growing in dry pendently places PRINTED IN GREAT BRITAIN AT THE UNIVERSITY PRESS OXFORD BY CHARLES BA TEY PRINTER TO THE UNIVERSITY