FLORA of GREAT BRITAIN and IRELAND Planned in Five Volumes, This Critical Flora Provides a Definitive Account of the Native Spec

Cambridge University Press 978-0-521-55336-0 - Flora of Great Britain and Ireland: Volume 2: Capparaceae – Rosaceae Peter Sell and Gina Murrell Frontmatter More information

FLORA OF GREAT BRITAIN AND IRELAND

Planned in fi ve volumes, this critical fl ora provides a defi nitive account of the native species, naturalised species, frequent garden escapes and casuals found in the British Isles. Full keys and descriptions will enable the user to name all plants occurring in the wild, plus some ornamental trees and shrubs. For the fi rst time, detailed accounts of all the large apomictic genera are given and many infraspecifi c variants included. Each species entry begins with the accepted Latin name, synonyms and the English name. A detailed description follows, including information on fl owering period, pollination and chromosome number. Separate descriptions are given for infraspecifi c taxa. Information on the status, ecology and distribution (including worldwide distribution) of the species and infraspecifi c taxa is also given. Clear black and white line drawings illustrate an extensive glossary and also illuminate the diagnostic features in a number of groups of plants.

PETER SELL (1929–2013) joined the Herbarium in the University of Cambridge’s Department of Plant Sciences in 1944, holding the post of Assistant Curator from 1972 until his retirement in 1997. From 1997 to 2013 his work there on this fl ora continued unabated, together with frequent visits to the University’s Botanic Garden throughout the fl owering and fruiting seasons. He was co-author of A Flora of Cambridgeshire (1964) and A Flora of the Maltese Islands (1977) and was involved in the whole Flora Europaea project, also published in fi ve volumes (1964–80) by Cambridge University Press.

GINA MURRELL joined the Herbarium in the University of Cambridge’s Department of Plant Sciences in 1966, where she held the post of Assistant Curator from 2002 until her retirement in 2011. She worked with Peter Sell over a period of 45 years, and together they collected a quarter of the British Herbarium’s 200,000 specimens.

© in this web service Cambridge University Press www.cambridge.org Cambridge University Press 978-0-521-55336-0 - Flora of Great Britain and Ireland: Volume 2: Capparaceae – Rosaceae Peter Sell and Gina Murrell Frontmatter More information

FLORA OF GREAT BRITAIN AND IRELAND

VOLUME 2 CAPPARACEAE – ROSACEAE

PETER SELL and GINA MURRELL Herbarium, Department of Plant Sciences University of Cambridge

Illustrated by Sarah Holme and Gina Murrell

University Printing House, Cambridge CB2 8BS, United Kingdom

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Library of Congress Cataloguing in Publication data Sell, P. D. (Peter D.) Flora of Great Britain, Ireland, Isle of Man, and the Channel Islands / Peter Sell and Gina Murrell. p. cm. Includes bibliographical references and index. Contents: – v. 5. Butomaceae–Orchidaceae. ISBN 0 521 55339 3 (hardback: v. 5) 1. Botany–British Isles. I. Murrell, Gina. II. Title. QK306.S44 1996 581.941–dc20 95-33535

ISBN 978-0-521-55336-0 Hardback

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To our Mentors

E DRED JOHN HENRY CORNER

J AMES EDGAR DANDY

H UMPHREY GILBERT-CARTER

H ARRY GODWIN

W ILLIAM THOMAS STEARN

S TUART MAX WALTERS

A LEXANDER STUART WATT

C YRIL WEST

Contents

Foreword ix Preface xi Acknowledgements xii Introduction xiii Conspectus of families xxi Text 1

68. CAPPARACEAE 1 77. MYRSINACEAE 86 69. BRASSICACEAE 1 78. PRIMULACEAE 87 70. RESEDACEAE 63 79. PITTOSPORACEAE 100 71. CLETHRACEAE 65 80. HYDRANGEACEAE 101 72. EMPETRACEAE 65 81. ESCALLONIACEAE 104 73. ERICACEAE 66 82. GROSSULARIACEAE 105 74. PYROLACEAE 83 83. CRASSULACEAE 108 75. MONOTROPACEAE 85 84. SAXIFRAGACEAE 120 76. DIAPENSIACEAE 86 85. ROSACEAE 135

New taxa and combinations 519 Abbreviations 524 Glossary 525 Index 541

Foreword

VOLUME 5 VOLUME 4

It has been one of the continuing satisfactions of my aca- It is for me a very real pleasure to add a further word to demic career in Cambridge that the University Herbarium, welcome this, the second volume of ‘Sell & Murrell’, as of which I was Curator from 1948 to 1973, has provided an this remarkable Flora is now widely known among British academic base for all my specialist interest in angiosperm botanists. Of course, this new volume, containing in par- taxonomy to develop. Indeed, I count myself doubly for- ticular the genus Hieracium, must rank as Peter’s very tunate that, 12 years after my retirement from academic own ‘labour of love’. One of the very special links that has life, the Herbarium, with its staff and visitors, still pro- grown up between Peter and me over our long- standing vides such a base where scholarship can be pursued for acquaintance in the pursuit of taxonomic botany must its own sake. With great pleasure I welcome this volume, be our steady, persistent enthusiasm for critical apomic- the fi rst of a set of fi ve promised to us by Peter Sell and tic genera. We do not have to explain or justify to each Gina Murrell. My association with Peter goes back more other our passions for, in my case, Alchemilla, and his for than half a century: though I was ‘senior partner’ in our Hieracium. I have to admit, however, that his task, with happy collaboration in the post-war Herbarium, ours was 412 named and described species of Hieracium in this vol- a symbiotic relationship from which we both greatly bene- ume, casts my puny efforts with British Alchemilla into fi ted, and I was delighted when Gina, who had been part the shade! of the team in the 1960s and 1970s, returned to the fold as Talking to Peter and Gina about the progress of this Herbarium Technician in 1991. remarkable Flora, I am encouraged by what I hear. I really As explained in the Preface, this project to write an believe that both Peter and I will live to see its completion, entirely new critical fl ora of the British Isles comes to fru- in spite of the fact that we both ‘creak a little at the joints’ ition some 20 years after an earlier scheme, in which the late – to use one of the common euphemisms we fi nd ourselves Professor David Valentine took a leading part, had failed to using from time to time to describe our state of health! fi nd any fi nancial support. Both Clive Stace to whose New One fi nal observation. How fortunate Peter is to have Flora of the British Isles (1991) Peter pays tribute in the such a remarkable fellow-author in Gina! Writing and pub- Preface, and Peter himself, were enthusiastic supporters lishing books involves much more than producing a draft of the Valentine project, and were prepared to play major text. Some of the skill is straightforward, if laborious; but parts in writing the Flora. It is fi tting that both these eminent some requires real understanding at the level of human British taxonomists should separately carry on the tradition relations, and both these skills are possessed in abundance that David Valentine so enthusiastically advocated. by Gina. So I conclude by saying to both Peter and Gina: Two aspects of this new critical Flora seem to be espe- keep up the good work to a successful conclusion. cially important. One concerns the acceptance, long over- due, of the ‘alien element’ in our fl ora as being equally S. M. Walters worthy of taxonomic study: in this respect Stace’s Flora 13 February 2002 represents a real change in attitude, which is to my mind unreservedly to be welcomed. The other, interestingly linked to the fi rst by many examples, concerns the taxo- VOLUME 3 nomic recognition and treatment of hybrids and infraspecifi c variants. British botany lacks any single reference Sadly, Max died on 11 December 2005. He strongly work from which the basic information about the variation approved of our whole attitude towards variation and intro- of British vascular plants can be found, yet this informa- ductions and fully understood the treatment of apomictic tion is increasingly needed by ecologists, conservation- genera. In Max, Cambridge had a leader in taxonomic bot- ists, molecular biologists and biochemists, who will, as any and conservation of our fl ora for over 50 years. See the century closes, determine the shape of much botanical my obituary in Watsonia 26: 215–217 (2007). study in universities and specialised institutions. The authors of this impressive work have set themselves Peter Sell a colossal task. They have made an excellent start, and we 2007 can only wish them a successful conclusion.

S. M. Walters 1996

x Foreword

VOLUME 2 the text, so that we hope that this volume is as close as is possible to what Peter would have wanted. We have usu- When Peter Sell died on 10 October 2013, he had writ- ally not attempted to update the accounts with information ten the text of the two remaining volumes of this Flora of published since they were completed. Before Roy Perry’s Great Britain and Ireland. Gina Murrell had already retired untimely death in November 2014 we continued to receive at the end of 2011 and moved away from Cambridge. We, great help from him, and we have also been very fortunate four friends of Peter, therefore agreed to see Volumes 2 in recruiting Jane Bulleid to assist with the proofreading. and 1 though the press, consulting Gina on key issues. As explained in the Acknowledgements in this volume, Arthur O. Chater Gwynn Ellis had already typed the text, and he and Roy R. Gwynn Ellis Perry had checked it and incorporated amendments in Philip H. Oswald consultation with Peter. Nevertheless further checking and Chris D. Preston correction were necessary, which we have tried to do with- November 2014 out altering the taxonomy or, in general, the substance of

Preface

For over 70 years I have worked in the herbarium at species in Stace’s fl ora and to add all the apomicts and Cambridge University on the British and European fl oras. many of the infraspecifi c variants, but it was too large I have collected about 30,000 numbers consisting of some a task to attempt to include all the biological informa- 50,000 specimens from most parts of the British Isles tion envisaged by the group in the 1970s. It was neces- and made many visits to Continental Europe. Particular sary, however, to have the help of another author who attention has been given to most critical genera: Betula, lived in Cambridge, to deal with the large amount of Cerastium, Chenopodium, Conyza, Crepis, Dactylorhiza, work involved. My eye fell upon Gina Murrell, who Euphrasia, Fumaria, Hieracium, Limonium, Pilosella, had worked with me in the 1960s and 1970s when we Prunus, Rhinanthus, Rumex, Salicornia, Salix, Scleranthus, were writing accounts for Flora Europaea, Flora of Sorbus and Ulmus; and in helping friends in various ways Turkey and A Flora of the Maltese Islands. The work I have considered the taxonomy of Alchemilla, Batrachian of one had complemented the work of the other and we Ranunculi, Potamogeton, Rubus and Taraxacum. I have were able to criticise one another without antagonism. also spent much time studying ecotypic and geograph- We started fi eldwork on this fl ora on 13 May 1987 by ical variation, in particular a comparison of those variants describing Ceratocapnos claviculata, which was fl ower- which occur on the coasts in dunes, shingle and saltmarsh ing on Dunwich Heath in Suffolk, in a snowstorm. The with those growing as arable weeds, and those in moun- last entry to the last volume was made in December 2012 tains. In these taxa I have carefully examined large num- when I added Rumex subalpinus; thus the fl ora took 25 bers of plants in a population to see how they vary and years to write. compared populations (not just one individual in each). The introduction in Volume 1 will set out the way in Rare and local plants have not been collected but notes of which our islands’ fl ora arrived after the last Ice Age, pro- the living plant have been made in the fi eld and many of vide a history of the Cambridge University Herbarium and them have been grown in Cambridge University Botanic Library, in which most of the work for this fl ora was car- Garden and we have examined them there. In the early ried out, and give examples of how the fl ora was divided years of the fl ora a large number of descriptions were up into species, subspecies, varieties and forms. made in the fi eld as well as the herbarium. This volume contains 18 families, 148 genera, 1122 It has long been my wish to publish this information in species, 65 subspecies, 221 varieties, 53 formae and 93 a critical fl ora of Great Britain and Ireland. In the 1970s hybrids. Volume 5 contains 28 families, 233 genera, 769 a group of us tried to get a grant to carry this out, but we species, 93 subspecies, 148 varieties, 22 formae and 182 were unsuccessful. Clive Stace then started work on his hybrids. Volume 4 contains seven families, 146 genera, New Flora of the British Isles, which was fi rst published 1098 species, 130 subspecies, 162 varieties, 27 formae in 1991, with a second edition in 1997 and a third in 2010. and 51 hybrids. Volume 3 contains 59 families, 299 gen- In it he gives only abbreviated descriptions and omits era, 996 species, 187 subspecies, 308 varieties, 102 for- most of the species in the large apomictic genera and mae and 235 hybrids. many of the infraspecifi c variants. Numerous introduced This volume contains the family Rosaceae with the species are included by Stace in a British and Irish fl ora partially apomictic genera Alchemilla, Cotoneaster, for the fi rst time, detailed descriptions and specimens of Potentilla, Rosa, Rubus and Sorbus. It was the most diffi - many of which are diffi cult to fi nd. In the third edition he cult to write, with the large apomictic genera and Rosa the has partially moved the main classifi cation over to DNA. most diffi cult of all. If we were starting this fl ora now we would do the same. I considered that it was possible for me to write a fl ora Peter Sell in fi ve volumes which gave a full description of all the

Acknowledgements

We are most indebted of all to Gwynn Ellis and Roy Perry, Bill and Joan Robinson we are grateful for letting us fre- who have not only put the whole of Volume 2 on computer quently raid their garden and for allowing some of their but have carefully read it and marked anything which vegetables to go to fl ower and seed so that we were able needed checking. Had they not done this the manuscript to collect complete plant specimens. P. D. S. owes a very might never have been published. They have also at vari- special debt to Brian and Rosemary Chapman. Every ous times helped us out over problems in the whole fl ora. Friday afternoon they used to lead him over unfamiliar Philip Oswald has not only translated into Latin the ground at Histon in Cambridgeshire and he tried to name new taxa in the whole fl ora but has answered many gen- every plant that he came across down to forma. This ena- eral questions concerning Greek and Latin and about the bled him to keep his eye in with plants in the fi eld as well layout of the fl ora. The late Max Walters translated much as in the herbarium. Swedish, German and French as well as discussing many In the library of the Department of Plant Sciences the problems of taxonomy. Chris Preston has answered many late Richard Savage and the current librarian Christine questions on the distribution of the taxa. The late W. H. Alexander have gone out of their way to track down rare Mills taught P. D. S. much about Rubus and showed him and obscure publications for us and somehow to fi nd a large number of taxa in the fi eld. Max Walters showed the books in the library during major alterations. At the P. D. S. all the Alchemillas in the fi eld and his cultivated University of Cambridge Botanic Garden Professor John plants in the University of Cambridge Botanic Garden. Parker and Dr Tim Upson allowed P. D. S. to continue Gordon Smith showed him all the Potentillas that he grew after his retirement to have a free run of the Garden, its in the Botanic Garden and his specimens are in CGE. library and herbarium, and the former endeavoured to P. D. S. discussed Acaena and Bergenia with the late Peter answer many of the diffi cult genetical and biological Yeo and examined his cultivated plants in the Botanic questions that we have put to him. Also at the Garden, Garden. the late James Cullen, Alexander Goodall, the late Clive Arthur Chater has acted as a very special sort of adjudi- King, Peter Kerley, Pete Michna, Sally Petitt, David cator. Whenever we worked out infraspecifi c variants which Stone, Tim Upson, Norman Villis and the late Peter were likely to occur in Cardiganshire, we telephoned him Yeo have given us much help. Since Gina’s retirement to give him the information, and he would either comment Christine Bartram has given P. D. S. immense help immediately or search for them at the fi rst opportunity. His in the University of Cambridge Herbarium and Sarah paper in Watsonia 24: 281–286 (2003) sets out the diffi cul- Holme has ably undertaken the drawing of the fi gures of ties in fi nding information on infraspecifi c taxa. His superb Alchemilla, Sorbus and Cotoneaster for this volume. Flora of Cardiganshire is now published and includes Professor Enid MacRobbie, Professor Roger Leigh, a great deal of infraspecifi c variation. Charlie Jarvis has Professor John Gray and Professor Sir David Baulcombe helped us while working on the Hortus Cliffortianus at allowed P. D. S. to continue to have full use of the herbar- the British Museum and answered questions on Linnaean ium and library after his retirement. typifi cation. Gina Douglas helped while working on the To Clive Stace we owe a very special debt. Had he not Linnaean collection at Burlington House. written his New Flora of the British Isles our task would To Mrs J. E. Dandy we owe a special debt for giving have been insurmountable. us the second copy of her husband’s manuscript of his detailed work on the nomenclature of the British fl ora. To Peter Sell

Introduction

HISTORICAL BACKGROUND The Botanical Society of the British Isles’ publication of the Atlas of the British Flora in 1962, edited by F. H. The fi rst real fl ora of these islands was John Ray’s Perring and S. M. Walters, and the Critical Supplement Catalogus Plantarum Angliae, et Insularum Adjacentium to the Atlas of the British Flora in 1968, edited by F. H. in 1670. The fi rst fl ora to use the Linnaean binomial sys- Perring, gave us a much better idea of the distribution of tem of nomenclature was William Hudson’s Flora Anglica our plants. New Atlas of the British & Irish Flora (2002) nearly a hundred years later in 1762. This was followed arrived when most of Volume 4 had been prepared for by William Withering’s A Botanical Arrangement of all press, but the fact that Chris Preston had checked most the Vegetables naturally growing in Great Britain in 1776, of our distributions meant that they were not much out the fi rst of many fl oras written primarily for the amateur. of date. For this volume the New Atlas was available James Sowerby’s English Botany, whose text was writ- to us and we were able to bring all distributions up to ten by J. E. Smith, was fi rst published between 1790 and date. The publication in 2003 of The Vice-County Census 1814. It presented for the fi rst time a complete set of col- Catalogue of the Vascular Plants of Great Britain, the oured illustrations of our plants, illustrations which are Isle of Man and the Channel Islands, edited by C. A. still unsurpassed for line and colour. The third edition, Stace et al., has greatly helped us to get the distributions published between 1863 and 1886, has inferior illustra- up to date. tions, but its text, rewritten by James Boswell Syme, is The publication of Clive Stace’s New Flora of the still important for its nomenclature and infraspecifi c taxa. British Isles in 1991, with a second edition in 1997 and a Three especially famous fl oras were produced in the third in 2010, and of D. H. Kent’s List of Vascular Plants nineteenth century. George Bentham’s Handbook of the of the British Isles in 1992 brought about the end of the British Flora in 1858 was written as a before-breakfast C. T. & W. era and has given us a completely up-to-date relaxation. In it keys appeared for the fi rst time in a British account of our fl ora. Major changes included the mov- fl ora. It was revised by J. D. Hooker in 1887. ing over of the main classifi cation to A. Cronquist’s An J. D. Hooker’s The Student’s Flora of the British Integrated System of Classifi cation of Flowering Plants Islands, fi rst published in 1870 and fi nally revised in (1981) and the inclusion of almost as many alien species 1884, had very clear and concise descriptions and was the as native ones. main fl ora used by many generations of botanists up until The aim of our fl ora is to supply full descriptions of all the 1950s. It is also important in that Hooker was one of the species in Stace’s fl ora, to include all the large apomic- the fi rst authors to make frequent use of the category of tic genera and as many infraspecifi c variants as practic- subspecies. able, and to add more information about hybrids, for which Charles Cardale Babington’s Manual of British Botany extensive use has been made of Stace’s Hybridization and fi rst appeared in 1843 and the tenth edition, revised by the Flora of the British Isles (1975). A. J. Wilmott, was published in 1922. It contains many critical species and varieties not in other fl oras, but the descriptions are not clear and without keys it is diffi cult THE CONTENTS OF THE FLORA to use. C. E. Moss’s Cambridge British Flora (1914–20) was The fl ora includes all the vascular plants, Lycopodiophyta very detailed and would have supplied a much needed crit- (Clubmosses), Equisetophyta (Horsetails), Polypodio- ical fl ora, but alas only two volumes were published. phyta or Pteridophyta (Ferns), Pinophyta (Conifers) and The arrival of ‘C. T. & W.’, A. R. Clapham, T. G. Tutin Magnoliophyta (Flowering plants). The list of plants is and E. F. Warburg’s Flora of the British Isles, in 1952 made up of all our native species, including apomicts, heralded the beginning of a new era in the study of British and all the introduced plants given in Stace, with some plants. It was the fi rst up-to-date treatment in the twentieth more added, particularly planted trees. E. J. Clement’s century. A much revised second edition appeared in 1962 and M. C. Foster’s Alien Plants of the British Isles and a third in 1987, when D. M. Moore replaced E. F. arrived in 1994 after we had written Volume 5, but we Warburg, who had died in 1966. This last edition included went through it and added as much information as pos- the information in Tutin et al., Flora Europaea 1–5 (1964– sible. It has been used continually while preparing the 80). The nomenclature had been brought up to date by J. remaining volumes. These alien taxa may be found to be E. Dandy in his List of British Vascular Plants in 1958 and more widespread when full attention is given to them. the work he did on this for Flora Europaea. Thus for the In his coverage of alien taxa Stace considers that inclu- fi rst time taxonomy and nomenclature had been brought in sion is merited when an alien is either naturalised (i.e. line with those of Continental Europe. permanent and competing with other vegetation or self-

xiv Introduction

perpetuating) or, if a casual, frequently recurrent so that CLASSIFICATION AND it can be found in most years. These criteria were applied NOMENCLATURE as much to garden escapes or throw-outs as to the unin- tentionally introduced plants, and rarity was not taken The classifi cation is taken from A. Cronquist’s An into consideration for any of them. Cultivated species Integrated System of Classifi cation of Flowering Plants were included if they are fi eld crops or forestry crops, or, (1981), with the exception that the main groups are called in the case of trees and shrubs only, ornamentals grown Divisions and the second groups Classes, following on a large scale. Stace’s aim has been to include “all taxa H. C. Bold, C. Alexopoulos & T. Deleveryas in Morphology that the plant-hunter might reasonably be able to fi nd ‘in of Plants and Fungi, ed. 4 (1980) and A. Cronquist, the wild’ in any one year”. Hedges have proved to be a A. Takhtajan & W. Zimmermann in ‘On the higher taxa diffi cult problem. Many were planted during enclosure, of Embryobionta’ in Taxon 15: 129–134 (1966) and as set often with non-native species or variants. In the last 50 out by one of us, P. D. S., in The Cambridge Cyclopedia years many more trees and shrubs have been planted in of Life Sciences in 1985. Stace used our classifi cation in new woods, along streets and roadsides, in parks and 1991 and 1997. In 2010 he moved to a slightly different estates, and implanted into old hedgerows. classifi cation similar to that of E. Haston, J. E. Richardson, A major attempt has been made in the last three volumes P. F. Stevens, M. W. Chase & D. J. Harris in Bot. Jour. published to include all the hedgerow plants and to include Linn. Soc. 161: 128–131 (2000) with orders inserted as all the aliens in wildfl ower seed. The best place to fi nd our defi ned by the Angiosperm Phylogeny Group in the same original species is by natural waterways, although imports journal, 161: 105–121 (2000). If we were starting the fl ora have also been put in there. Usually plants in gardens are now we would follow exactly that of the Phylogeny Group not mentioned at all, but some species that seed freely and including putting the monocotyledons at the beginning. spread over areas of garden and lawn where they are not One of us (P. D. S.) has specialised in nomenclature planted are included. Most of the species which Stace has for many years and it is here made as accurate as possible mentioned but not numbered or included in his keys are according to the latest International Code of Botanical here included, while a few have been left out altogether. Nomenclature. The names of genera and species differ little from those in Stace. New taxa and such changes in GEOGRAPHICAL AREA nomenclature and taxonomy as do occur are published at the end of the volume. The fl ora deals with the British Isles and includes England, No rules have been made about the number of syn- Scotland and Wales, collectively known as Great Britain, onyms given, as many as possible being included, but an Northern Ireland and Eire together forming Ireland, the attempt has been made to include all names used in British Isle of Man, and the Channel Islands, which include Jersey, and Irish Floras. The abbreviation auct. following a name Guernsey, Alderney, Sark, Herm and various small islands. means only that the name has not been accepted for the In these respects it follows Stace (1991, 1997 and 2010). plant; it does not mean that the type has been checked and The smallest geographical area usually referred to is the name rejected. Only in the case of a later homonym, the county. This sometimes includes more than one botan- which has been checked, does the word non and an author ical vice-county, for which we use the terminology in J. E. follow the name and author. This inclusion of numerous Dandy’s Watsonian Vice-counties of Great Britain (1969). synonyms often shows how a species has moved from one For Great Britain we have used the boundaries adopted genus to another over the years. by H. C. Watson in 1873 in Topographical Botany and in The English names for the species follow Stace as far Ireland by R. L. Praeger in 1901 in Irish Topographical as possible, and where they are missing for additional spe- Botany. These are the vice-counties used by botanists, cies they have been created. which have the benefi t of not changing at intervals as do In whatever way you arrive at your identifi ed species, the political counties. With rare or local species the actual your plant should fi t exactly the detailed description in the place or area may be given. The extra-limital distributions text. If a diffi cult plant has any chance of being identifi ed are those given in Clapham, Tutin & Moore (1987) with as very detailed notes of every character should be made in much correcting as we and Chris Preston can give them. the fi eld. All too often a miserable bit of a plant rotting in a Russia and Yugoslavia have been used in the sense of the plastic bag is all that is available, as after a long day in the old USSR and Yugoslavia before political disruptions. fi eld the botanist puts his meal and bed fi rst.

Shetland Islands

100 km

Orkney Islands

GREAT BRITAIN Outer Hebrides Scottish Highlands

Inner Hebrides

IRELAND Lake District River Tees

Yorkshire Dales

Peak District Isle of Man Connemara River Humber The Wash East The Snowdonia Anglia Burren Fens The Broads Brecon Beacons Breckland River Thames River Severn

Lundy Island

Isles of Scilly Alderney CHANNEL FRANCE Guernsey ISLANDS Jersey

BRITISH ISLES

Adapted from Stace, C. A. (2010). New Flora of the British Isles. Edn 3. Cambridge University Press, Cambridge. Reproduced with permission.

112

100 km 111

108 109

107 110 105 106

95 93 94 96 104 92 97 91 Scotland 89 90 88 103 98 87 85 99 86 84 82 102 76 83 81 101 100 77 78 GREAT BRITAIN 68 75 79 80 IRELAND 72 35 67 40 73 34 39 74 70 66 36 England 69 33 37 38 65 62 27 28 32 71 29 30 64 61 26 31 Isle of Man 60 25 24 22 16 17 23 59 63 54 18 21 15 19 52 51 58 57 49 56 14 50 9 20 53 10 48 13 39 28 27 8 11 40 55 7 47 2 12 31 29 6 38 32 25 46 43 37 26 4 Wales 1 5 36 30 19 44 42 23 3 45 33 24 20 35 18 41 34 21 7 22 17 16 6 15 8 12 5 Channel Islands 11 14 4 13 9 10 CI 3 2

VICE-COUNTIES OF THE BRITISH ISLES

Adapted from Stace, C. A. (2010). New Flora of the British Isles. Edn 3. Cambridge University Press, Cambridge. Reproduced with permission.

ENGLAND, WALES, SCOTLAND, ISLE OF MAN

1. West Cornwall 39. Staffordshire 77. Lanarkshire 2. East Cornwall 40. Shropshire 78. Peebles-shire 3. South Devon 41. Glamorganshire 79. Selkirkshire 4. North Devon 42. Breconshire 80. Roxburghshire 5. South Somerset 43. Radnorshire 81. Berwickshire 6. North Somerset 44. Carmarthenshire 82. East Lothian 7. North Wiltshire 45. Pembrokeshire 83. Midlothian 8. South Wiltshire 46. Cardiganshire 84. West Lothian 9. Dorset 47. Montgomeryshire 85. Fifeshire 10. Isle of Wight 48. Merionethshire 86. Stirlingshire 11. South Hampshire 49. Caernarvonshire 87. West Perthshire 12. North Hampshire 50. Denbighshire 88. Mid Perthshire 13. West Sussex 51. Flintshire 89. East Perthshire 14. East Sussex 52. Anglesey 90. Forfarshire 15. East Kent 53. South Lincolnshire 91. Kincardineshire 16. West Kent 54. North Lincolnshire 92. South Aberdeenshire 17. Surrey 55. Leicestershire 93. North Aberdeenshire 18. South Essex 56. Nottinghamshire 94. Banffshire 19. North Essex 57. Derbyshire 95. Morayshire 20. Hertfordshire 58. Cheshire 96. East Inverness-shire 21. Middlesex 59. South Lancashire 97. West Inverness-shire 22. Berkshire 60. West Lancashire 98. Main Argyllshire 23. Oxfordshire 61. South-east Yorkshire 99. Dunbartonshire 24. Buckinghamshire 62. North-east Yorkshire 100. Clyde Islands 25. East Suffolk 63. South-west Yorkshire 101. Kintyre 26. West Suffolk 64. Middle-west Yorkshire 102. South Ebudes 27. East Norfolk 65. North-west Yorkshire 103. Middle Ebudes 28. West Norfolk 66. Co. Durham 104. North Ebudes 29. Cambridgeshire 67. South Northumberland 105. West Ross-shire 30. Bedfordshire 68. Cheviotland 106. East Ross-shire 31. Huntingdonshire 69. Westmorland 107. East Sutherland 32. Northamptonshire 70. Cumberland 108. West Sutherland 33. East Gloucestershire 71. Isle of Man 109. Caithness 34. West Gloucestershire 72. Dumfries-shire 110. Outer Hebrides 35. Monmouthshire 73. Kirkcudbrightshire 111. Orkney Islands 36. Herefordshire 74. Wigtownshire 112. Shetland Islands 37. Worcestershire 75. Ayrshire 38. Warwickshire 76. Renfrewshire

IRELAND

H1. South Kerry H15. South-east Galway H29. Co. Leitrim H2. North Kerry H16. West Galway H30. Co. Cavan H3. West Cork H17. North-east Galway H31. Co. Louth H4. Mid Cork H18. Offaly H32. Co. Monaghan H5. East Cork H19. Co. Kildare H33. Fermanagh H6. Co. Waterford H20. Co. Wicklow H34. East Donegal H7. South Tipperary H21. Co. Dublin H35. West Donegal H8. Co. Limerick H22. Meath H36. Tyrone H9. Co. Clare H23. West Meath H37. Co. Armagh H10. North Tipperary H24. Co. Longford H38. Co. Down H11. Co. Kilkenny H25. Co. Roscommon H39. Co. Antrim H12. Co. Wexford H26. East Mayo H40. Co. Londonderry H13. Co. Carlow H27. West Mayo H14. Laois H28. Co. Sligo

xviii Introduction

VARIATION Where species grade gradually into one another over large distances, as the species of Larix do round the north- The recording of variation is most important for both ern hemisphere, and at given points the whole population is ecology and conservation, and even more important for uniformly intermediate, this is regarded as a cline. Where gardeners, who go out of their way both to create and to two populations with differing ecological preferences grow conserve prominent variants. adjacently, as in Geum rivale and urbanum, there is often Infraspecifi c variation is usually recorded by the recog- an area in which variable intermediates occur. This is also nition of subspecies, varieties, formae and cultivars. These often called a cline, but it is really only so statistically, and taxa differ chiefl y in ecology and distribution. A forma is a we prefer to call it a variable hybrid zone. If you look for plant with a one- or two-gene difference which occurs with these things you will be surprised how often they exist, and one or more other forms in a mixed population for most or clear-cut species, even apomicts, are not so clear-cut as we all of its range. The term variety is used when one of these are made to believe. formae becomes more or less dominant in a particular eco- Dick Brummitt and Arthur Chater, writing in Watsonia logical area; that is it forms an ecotype. The term subspe- 23: 161 (2000) about the genus Calystegia, say: cies is used when one of these formae becomes dominant The whole genus, in which some 25 species world-wide may con- in a geographical area; that is it forms a race. A cultivar veniently be recognised, is taxonomically diffi cult, and few if any is a forma which is selected by horticulturalists and per- of the species are morphologically clear-cut. They mostly vary petuated, usually vegetatively. Because ecotypes and races considerably over their ranges and merge geographically one into have become adapted morphologically to different condi- another, and division into species and subspecies is of necessity tions over a long period, it is likely that their physiology somewhat arbitrary. and biochemistry, and indeed their whole biology, is differ- We fi nd this true of many groups when their whole range ent. Also, as they often fl ower at different periods, their pol- is considered. linators may be different and, if climatic conditions alter, If the origin of taxa is considered there are even more one ecotype may be better able to survive than another. diffi cult problems. During the Quaternary cold stages Variation thus becomes very important in conservation. massive glaciation from the north caused forests to retreat Because the Biological Flora of the British Isles has lumped southwards and come up against other different fl oras all its information under species it can be highly mislead- and in some cases to hybridise with them. With climatic ing when applied to individual populations. It is unfortunate amelioration the forests advanced north again, often per- that many botanists tend to ignore variation completely, and haps by a different path from the one by which they went they will certainly ignore it if it has no name at all; sub- south, bringing a fresh range of plants to join those species species are usually more often recognised than varieties. that survived in refugia in the cold areas. Richard West in Sometimes it is more important to conserve one variety Plant Life of the Quaternary Cold Stages: Evidence from rather than another, e.g. the Chilterns Orchis militaris var. the British Isles (2001, p. 263) writes: tenuifrons is endemic, while the Suffolk var. militaris occurs in Continental Europe (unfortunately seeds from Suffolk This overall view shows the cold stage stadial fl ora to have a long and from possible hybrids seem to have been planted in and complex history, originating in the latest Tertiary, occupying the Chilterns in the 1970s); Liparis loeselii var. ovata is a major part of Quaternary time in our area, and surviving short rare in distribution, but frequent where it occurs, whereas periods of forest dominance at times of climatic amelioration. It var. loeselii is rare in Britain but occurs on the continent. is not surprising that the taxonomy of the species concerned is very complex. Sometimes the variant will tell us whether the plant is native or not; e.g. Leucojum aestivum subsp. aestivum is native After the forest clearances of the Neolithic about 5000 while subsp. pulchellum is a naturalised garden escape. years ago and the agricultural revolution which followed, Escaped cultivars are named wherever they can be eas- some of the species of open habitats, particularly of ily recognised and are considered important. All apomicts, coastal areas, developed ecotypes which became agricul- where possible, are treated as species, long experience tural weeds; others were actually brought in by early Man showing that any sort of lumping deprives them of being himself. Indeed, the weeds of Cornwall, East Anglia and recognised as having an interesting ecology or distribution. Scotland may have been brought in by different races of Isolated plants that are different have not been named, but Man, at different times, from entirely different areas. the problem is a diffi cult one, as a population of hundreds To add to this state of affairs Man has brought plants of plants can almost disappear in a few years. Hybrids are from all over the world into gardens. Crops have brought dealt with as fully as possible, especially those that spread in weeds from many countries. In recent years conserva- vegetatively. No serious attempt has been made to decide tionists have sown wildfl ower seeds of species that are not on the correct infraspecifi c rank as taxa are often both eco- native or of continental races of native ones. They have logical and geographical. Uniformity of infraspecifi c rank also implanted many trees and shrubs in our hedgerows is often produced in a species or genus, but usually the and created new woods, often with non-native species only important thing considered is that a morphologically or varieties. Oliver Rackham has coined the name ‘look- recognisable taxon has a name. alikes’ for these.

Introduction xix

It can thus be seen that many of our species are far from Scarce plants in Britain. 1994. Peterborough. uniform genetically. Apomictic species and many ecotypic Tutin, T. G. et al. (Edits.) Flora Europaea. 1–5. 1964–80. varieties are probably more uniform. Cambridge. DNA may help us to understand these problems, but will Walters, S. M. / Cullen, J. et al. (Edits.) The European we ever have time and money to look in detail at the whole garden fl ora. 1–6. 1984–2000. Cambridge. of our fl ora, let alone that of the whole world? A solitary example of each taxon is in our opinion inadequate. Many other books and journals were consulted, mainly in the University of Cambridge Department of Plant Sciences, including the N. D. Simpson collection of local LITERATURE AND HERBARIA fl oras, and in the Cory Library at the Botanic Garden. CONSULTED Where these references were considered to be important for particular plants, we have cited them under the family During the writing of the fl ora the following books were or genus concerned. consulted as appropriate. This number increased as we The University herbaria at Cambridge, on which the went along and a full list will be given in Volume 1. fl ora is mainly based, are ideal for the study of the British fl ora for the following reasons: Boreau, A. Flore du centre de la France. 1 and 2. 1857. Paris. (This contains a large number of segregate species 1. The large British collection contains specimens from of A. Jordan, which he grew in cultivation for many most of the main collectors of British plants from years and which are now recognised as infraspecifi c taxa 1800 onwards, including sets of published exsiccatae or apomictic species.) and specimens sent through the Botanical Exchange Clapham, A. R., Tutin, T. G. & Moore, D. M. Flora of the Clubs. Most of the critical species have been named by British Isles. Ed. 3. 1987. Cambridge. experts. Dandy, J. E. List of British vascular plants. 1958. London. 2. The British herbarium contains some 50,000 specimens Hegi, G. Illustrierte Flora von Mitteleuropa. Ed. 1. 1906– collected by us in the last 50 years. The specimens are 31. München. Ed. 2. 1936– München. Ed. 3. 1966– accompanied by detailed fi eld notes and photographs München. and are often of critical species or infraspecifi c taxa. Kent, D. H. List of vascular plants of the British Isles. Often a gathering may consist of more than one sheet, 1992. London. particularly of trees, which may have been visited three Perring, F. H. & Walters, S. M. (Edits.) Atlas of the British or four times. fl ora. 1962. London and Edinburgh. 3. There is a good herbarium of Continental European Perring, F. H. (Edit.) Critical supplement to the atlas of the plants with which to compare the British plants. British fl ora. 1968. London. 4. The world collection contains over 50,000 sheets of Preston, C. D. & Croft, J. M. Aquatic plants in Britain and John Lindley’s herbarium made when he was secretary Ireland. 1997. Colchester. of the Royal Horticultural Society, when plants were Preston, C. D., Pearman, D. A. & Dines, T. D. (Edits.) New coming into the country from all parts of the world, atlas of the British & Irish fl ora. 2002. Oxford. and the C. M. Leman collection, named by George Bentham and put together at the same time. These col- Reynolds, S. C. P. A catalogue of alien plants in Ireland. lections are very important as regards the alien spe- 2002. Glasnevin. cies when considered in conjunction with the Botanic Stace, C. A. (Edit.) Hybridization and the fl ora of the British Garden, the herbarium and recent gatherings of alien Isles. 1975. London, New York and San Francisco. specimens. Stace, C. A. New fl ora of the British Isles. Ed. 1. 1991. 5. The Botanic Garden herbarium contains a large collec- Cambridge. Ed. 2. 1997. Cambridge. Ed. 3. 2010. tion of cultivated plants. Cambridge. Stace, C. A. et al. (Edits.) Vice-county census catalogue of Thus the libraries, herbaria, our own fi eld notes and the vascular plants of Great Britain. 2003. London. plants grown in the Botanic Garden have enabled us to Stearn, W. T. Botanical Latin. Ed. 4. 1992. Newton Abbot. do most of the work in Cambridge. Over many years Stewart, A., Pearman, D. A. & Preston, C. D. (Edits.) books and specimens elsewhere have been consulted.

Conspectus of families

Kingdom PLANTAE

Volume 1.

Division 1. LYCOPODIOPHYTA

Order 1 . LYCOPODIALES

1. LYCOPODIACEAE

Order 2 . SELAGINELLALES

2. SELAGINELLACEAE

Order 3 . ISOETALES

3. ISOETACEAE

Division 2. EQUISETOPHYTA

Order 1 . EQ UISETALES

4. EQUISETACEAE

Division 3. POLYPODIOPHYTA (PTERIDOPHYTA)

Order 1 . OPHIOGLOSSALES

5. OPHIOGLOSSACEAE

Order 2 . OSMUNDALES

6. OSMUNDACEAE

Order 3 . PTERIDALES

7. ADIANTACEAE 8. PTERIDACEAE

Order 4 . MARSILEALES

9. MARSILEACEAE

Order 5 . HYMENOPHYLLALES

10. HYMENOPHYLLACEAE

xxii Conspectus of families

Order 6 . POLYPODIALES

11. POLYPODIACEAE

Order 7 . DICKSONIALES

12. CYATHEACEAE 13. DICKSONIACEAE

Order 8 . DENNSTAEDTIALES

14. DENNSTAEDTIACEAE 18. DAVALLIACEAE

15. THELYPTERIDACEAE 19. DRYOPTERIDACEAE

16. ASPLENIACEAE 20. BLECHNACEAE

17. WOODSIACEAE (ATHYRIACEAE)

Order 9 . SA LVINIALES

21. AZOLLACEAE

Division 4. PINOPHYTA

Class 1 . PINOPSIDA Order 1 . GINKGOALES

21A. GINKGOACEAE

Order 2 . PI NALES

22. PINACEAE 24. CUPRESSACEAE

23. TAXODIACEAE 25. ARAUCARIACEAE

Class 2 . TAXOPSIDA Order 1 . TAXALES

26. TAXACEAE

Division 5. MAGNOLIOPHYTA

Class 1 . MAGNOLIOPSIDA (DICOTYLEDONES) Subclass 1 . M AGNOLIIDAE Order 1 . M AGNOLIALES

27. MAGNOLIACEAE

Order 2 . L AURALES

28. LAURACEAE

Conspectus of families xxiii

Order 3 . ARISTOLOCHIALES

29. ARISTOLOCHIACEAE

Order 4 . NYMPHAEALES

30. NYMPHAEACEAE 31. CERATOPHYLLACEAE

Order 5 . RANUNCULALES

32. RANUNCULACEAE 33. BERBERIDACEAE

Order 6 . PA PAVERALES

34. PAPAVERACEAE 35. FUMARIACEAE

Subclass 2 . HAMAMELIDAE Order 1 . HAMAMELIDALES

36. PLATANACEAE

Order 2 . U RTICALES

37. ULMACEAE 39. MORACEAE

38. CANNABACEAE 40. URTICACEAE

Order 3 . JUGLANDALES

41. JUGLANDACEAE

Order 4 . MYRICALES

42. MYRICACEAE

Order 5 . FAGALES

43. FAGACEAE 45. CORYLACEAE

44. BETULACEAE

Subclass 3 . CA RYOPHYLLIDAE Order 1 . C A RYOPHYLLALES

46. PHYTOLACCACEAE 50. PORTULACACEAE

46A. NYCTAGINACEAE 51. BASELLACEAE

47. AIZOACEAE 52. CARYOPHYLLACEAE (ILLECEBRACEAE) 48. CHENOPODIACEAE

49. AMARANTHACEAE

xxiv Conspectus of families

Order 2 . P O LYGONALES

53. POLYGONACEAE

Order 3 . PLUMBAGINALES

54. PLUMBAGINACEAE

Subclass 4 . DILLENIIDAE Order 1 . DILLENIALES

55. PAEONIACEAE

Order 2 . THEALES

56. ELATINACEAE 57. CLUSIACEAE (GUTTIFERAE; HYPERICACEAE)

Order 3 . M A LVALES

58. TILIACEAE 59. MALVACEAE

Order 4 . NEPENTHALES

60. SARRACENIACEAE 61. DROSERACEAE

Order 5 . VIOLALES

62. CISTACEAE 65. FRANKENIACEAE

63. VIOLACEAE 66. CUCURBITACEAE

64. TAMARICACEAE

Order 6 . SALICALES

67. SALICACEAE

Volume 2.

Order 7 . CAPPARALES

68. CAPPARACEAE 70. RESEDACEAE

69. BRASSICACEAE (CRUCIFERAE)

Order 8 . ERICALES

71. CLETHRACEAE 74. PYROLACEAE

72. EMPETRACEAE 75. MONOTROPACEAE

73. ERICACEAE

Order 9 . DIAPENSIALES

76. DIAPENSIACEAE

Conspectus of families xxv

Order 10. PRIMULALES

77. MYRSINACEAE 78. PRIMULACEAE

Subclass 5 . ROSIDAE Order 1 . ROSALES

79. PITTOSPORACEAE 83. CRASSULACEAE

80. HYDRANGEACEAE 84. SAXIFRAGACEAE

81. ESCALLONIACEAE 85. ROSACEAE

82. GROSSULARIACEAE

Volume 3.

Order 2 . FA BALES

86. MIMOSACEAE 88. FABACEAE (LEGUMINOSAE)

87. CAESALPINIACEAE

Order 3 . P ROTEALES

89. ELAEAGNACEAE

Order 4 . HALORAGALES

90. HALORAGACEAE 91. GUNNERACEAE

Order 5 . M Y RTALES

92. LYTHRACEAE 94. MYRTACEAE

93. THYMELAEACEAE 95. ONAGRACEAE

Order 6 . CORNALES

96. CORNACEAE 96A. GARRYACEAE

Order 7 . SANTALALES

97. SANTALACEAE 98. VISCACEAE

Order 8 . CELASTRALES

99. CELASTRACEAE 100. AQUIFOLIACEAE

Order 9 . EUPHORBIALES

101. BUXACEAE 102. EUPHORBIACEAE

Order 10. RHAMNALES

103. RHAMNACEAE 104. VITACEAE

xxvi Conspectus of families

Order 11. LINALES

105. LINACEAE

Order 12. POLYGALALES

106. POLYGALACEAE

Order 13. SAPINDALES

107. STAPHYLEACEAE 111. ANACARDIACEAE

108. SAPINDACEAE 112. SIMAROUBACEAE

109. HIPPOCASTANACEAE 113. RUTACEAE

110. ACERACEAE

Order 14. GERANIALES

114. OXALIDACEAE 117. TROPAEOLACEAE

115. GERANIACEAE 118. BALSAMINACEAE

116. LIMNANTHACEAE

Order 15. APIALES

119. ARALIACEAE 120. APIACEAE (UMBELLIFERAE)

Subclass 6 . ASTERIDAE

Order 1 . GENTIANALES

121. GENTIANACEAE 122. APOCYNACEAE

Order 2 . SOLANALES

122A. NOLANACEAE 126. MENYANTHACEAE

123. SOLANACEAE 127. POLEMONIACEAE

124. CONVOLVULACEAE 128. HYDROPHYLLACEAE

125. CUSCUTACEAE

Order 3 . LAMIALES

129. BORAGINACEAE 131. LAMIACEAE (LABIATAE)

130. VERBENACEAE

Order 4 . CALLITRICALES

132. HIPPURIDACEAE 133. CALLITRICHACEAE

Order 5 . PLANTAGINALES

134. PLANTAGINACEAE

Conspectus of families xxvii

Order 6 . S C ROPHULARIALES

135. BUDDLEJACEAE 139. GESNERIACEAE

136. OLEACEAE 140. ACANTHACEAE

137. SCROPHULARIACEAE 140A. BIGNONIACEAE

138. OROBANCHACEAE 141. LENTIBULARIACEAE

Volume 4.

Order 7 . CAMPANULALES

142. CAMPANULACEAE

Order 8 . RUBIALES

143. RUBIACEAE

Order 9 . DIPSACALES

144. CAPRIFOLIACEAE 146. VALERIANACEAE

145. ADOXACEAE 147. DIPSACACEAE

Order 10. ASTERALES

148. ASTERACEAE (COMPOSITAE)

Volume 5.

Class 2. LILIOPSIDA (MONOCOTYLEDONES)

Subclass 1 . ALISMATIDAE Order 1 . ALISMATALES

149. BUTOMACEAE 150. ALISMATACEAE

Order 2 . HYDROCHARITALES

151. HYDROCHARITACEAE

Order 3 . NA JA DALES

152. APONOGETONACEAE 156. RUPPIACEAE

153. SCHEUCHZERIACEAE 157. NAJADACEAE

154. JUNCAGINACEAE 158. ZANNICHELLIACEAE

155. POTAMOGETONACEAE 159. ZOSTERACEAE

xxviii Conspectus of families

Subclass 2 . ARECIDAE Order 1 . ARECALES

160. ARECACEAE (PALMAE)

Order 2 . ARALES

161. ARACEAE 162. LEMNACEAE

Subclass 3 . COMMELINIDAE Order 1 . COMMELINALES

163. COMMELINACEAE

Order 2 . ERIOCAULALES

164. ERIOCAULACEAE

Order 3 . JUNCALES

165. JUNCACEAE

Order 4 . CYPERALES

166. CYPERACEAE 167. POACEAE (GRAMINEAE)

Order 5 . TYPHALES

168. SPARGANIACEAE 169. TYPHACEAE

Subclass 4 . ZINGIBERIDAE Order 1 . B ROMELIALES

170. BROMELIACEAE

Subclass 5 . LILIIDAE Order 1 . LILIALES

171. PONTEDERIACEAE 173. IRIDACEAE

172. LILIACEAE (ALLIACEAE; 174. AGAVACEAE AMARYLLIDACEAE; TRILLIACEAE)

175. DIOSCOREACEAE Order 2 . ORCHIDALES

176. ORCHIDACEAE