Stusies in the Family Thelypteridaceae.III. A new system of genera in the Old World R.E. Holttum Royal Botanic Gardens, Kew scheme of classification in is based the examination The new presented this paper on which of all species in the family Thelypteridaceae I have been able to trace in the Old have of World. I gradually compiled a list about 700 names(basionyms) andhaveexamined other authentic material of all but small and in the of type or a proportion; course study of herbaria I have notedabout another which to be specimens in many 50 species appear undescribed. I have attempted to re-describeallthe previously-named species, noting char- acters not mentionedinexisting descriptions, especially the detaileddistribution of hairs and those the and stalk of and characters of is glands, including on body sporangia, spores. It that there some detected which refer probable remain published names, not yet by me, of the but I think there to species family, are not many. I have also made a study of all generic and infrageneric names which are typifiable of have tried and fix the by species Thelypteridaceae, and in doubtful cases I to clarify As in the second this series 18: typification. already reported paper of (Blumea 195 —215), I have had the help of Dr. U. Sen and Miss N. Mittrain examining anatomical and other microscopic characters of some type species, and hope to present further information of this kind later. the of As a beginning, I adopted generic arrangement Ching (Acta Phytotax. Sinica 8: with the exclusion of I does 289—335. 1963) Hypodematium (which am sure not belong to the family) and the addition of Sphaerostephanos and Haplodictyum (which Ching in that wrongly excluded 1940 and did not mention in 1963). It was soon apparent to me the of had of the included type species Cyclosorus little relationship to most species in it by Ching and Copeland (Genera Filicum, 1947), and this led me to ask Dr. Sen to examine detail and with of result of this it in to compare it the type species Thelypteris. As a inves- isolated tigation, I concluded that Cyclosorus s. str. is a small and rather group, in many of from it ways a tropical counterpart Thelypteris s. str. Apart Cyclosorus, appears to me that natural did Ching's genera of 1963 are mostly groups, but that he not characterize them of number of Malesian clearly. Naturally he omitted consideration a large species; these complicate the problem more than he realized, and the species falling within his of be concept Cyclosorus must subdivided, even after removing the type species. The devoted considerable other author who has recently a study to this family in Iwatsuki Asia is (Mem. Coll. Sci. Univ. Kyoto B, 30: 21—51. 1963; 31: I—40. 1964 and date of 125 —197. 1965); his work includes the most comprehensive study to comparative morphology within the family. He made some modifications in Ching's scheme of these Like he had little classification, but do not seem to me an improvement. Ching, Malesian which form the of the the acquaintance with the species major part family in Old World. Morton's of the has conspectus family (Amer. Fern. J. 53: 153 —154. 1963) little reference to species of the Old World. 17 18 BLUMEA VOL. No. XLX, I, 1971 African have close relatives Asia and and it Most species appear to no in Malesia, seems to me possible that at least some of them have a relationship to species-groups in the Americas. Apart from these, it looks probable that the only species-groups common to and Worlds the small the Old New are groups of Thelypteris, Oreopteris, Phegopteris, and limited the and the Stegnogramma, Cyclosorus (as in present paper) larger group named has the Old Thelypteris subg. Cyclosoriopsis by Iwatsuki; the latter more species in World in the New. it than Thus seems to me possible to present an analysis of the Old World without the likelihood that will be species (omitting some in Africa) it upset or upset by study ofNew World species. I hope the time is not far distant when the latter will receive I is it will a new analysis. realize that the present attempt only tentative, and probably least throw the raise many new problems. At I hope it will some light on aspects of subject which have hitherto been little considered. Nearly all species already have names that in Thelypteris, so authors who prefer to regard my genera as subgenera or sections of Thelypteris can easily do so. what to to be the of characters which In generic diagnoses I give appear me assemblages distinctive of and then cite the In I have indicated are each, type species. most cases not all all the older generic synonyms; nearly species were included inDryopteris by Christen- and in other earlier sen ( Index Filicum, 1905, and three Supplements) variously genera by authors. Copeland (Gen. Fil. 1947; Fern Fl. Philip, i960) included nearly all in Lastrea and in of Cyclosorus. I do not here propose transfer of specific epithets except the case type intend when I made species. I to publish the necessary new combinations have mono- here of graphic studies of the various genera; but I give a fairly complete hst basionyms each these have which I believe belong to genus. Some of will later to be reduced to and there will be be added. synonymy, new species to Major subdivisions in the family are not easy to discern. The present great diversity within it is probably a rather recent development. Fossils with anastomosis of veins of have been found lower rocks both and the Thelypteroid type in Tertiary in Europe America (see note under Haplodictyum) but they lack the kind of diagnostic detail now the Old World seen to be necessary to distinguish species-groups within the family. In the main is that the here numbered which include generalization possible genera 16—21, of all Old World form a natural discussion under 55 % species, group (see Pronephrium); all have the base number If all these included in so far as known, chromosome 36. were one genus, its name would have to be Stegnogramma Bl. The rest of the genera constitute a number of smaller rather isolated looks me as if and groups. It to Mesophlehion, Chingia, be inter-related. and form isolated Glaphyropteridopsis may Coryphopteris Parathelypteris an of free-veined with short group species with small fronds, the majority ( Coryphopteris ) erect have hairs. of the caudex; many some septate They may preserve some primitive Old characters of the family, but do not look like a stock from which the remaining World genera can have arisen. Prof. T. M. Harris has described a Jurassic fossil fern Aspidistes thomasii (The Yorkshire Jurassic Flora 1: 181. 1961) which has spherical glands on the lower surface of the lamina, with and of and much as in Coryphopteris, sporangia sori comparable size form; the frond those of may, however, have been tripinnate and the leaflets are more like Pseudophegop- of These teris. The spores are trilete, much as in Trigonospora the present arrangement. facts may indicate that evolution in the family has resulted in primitive characters being of dispersed among different species-groups today. The family Thelypteridaceae shows many resemblances to the genus Cyathea and I these be believe to significant. They may be summarized as follows. Shape of leaflets (pinnae in most Thelypteroids, pinnules in Cyathea). These have an R. E. Holttum: Studies in the family Thelypteridaceae 111 19 almost symmetrical base, sides parallel for most of their length, edges lobed with almost symmetric pinnate venation in each lobe. of Shape of fronds. Many pinnae are of similar length, changes near base and apex frond being relatively abrupt in most cases. In some species the lower pinnae are progressively smaller almost down that the in to the caudex, so true stipe is short; others the lowest pinnae are at most the In related slightly reduced, stipe being elongate. Cyathea closely species may have character the each has one or other; in Thelypteridaceae species-group (or genus) its own character of this kind. Hairs on upper surface of rachis and costae. These are non-glandular and they are antrorse- consist of several in of ly curved. In Cyathea they cells, Thelypteridaceae usually one few hairs cell, but in a species-groups septate occur ((Coryphopteris, Stegnogramma). of rachis, costae, and other parts are more varied and more distinctive of individual species. There line the Aerating tissue. is a of aerating tissue (with stomata in epidermis) down each side of the rachis. This connects the decurrent base of the lamina of one pinna with ofthe below there the the edge pinna it. In addition is a patch of aerating tissue at base of each pinna on the abaxial side. This patch is always conspicuous on young fronds and is slightly prominent in some species of Cyathea; in some Thelypteroids it becomes much swollen or elongate (see note below on aerophore characters). Indusiate round sori seated on a vein, with vascular tissue passing from the vein into the base of the sorus. Cyathea species have somewhat less specialized sori and sporangia, and a much more vascular than be an older complex system Thelypteroids; they are likely to group (though there little is evidence from fossils) but they are still a very active one. Thelypteridaceae look like somewhat simplified, more efficient, and more diversified relatives of Cyathea, looks and they are certainly in a very active state of development. If one to cytology for evidence of relationships, one finds that all species of Cyathea so far examined have a double numbers found chromosome number 69.