THE BRYOPHYTES OF CORNWALL AND THE ISLES OF SCILLY by David T. Holyoak Contents Acknowledgements ................................................................................ 2 INTRODUCTION ................................................................................. 3 Scope and aims .......................................................................... 3 Coverage and treatment of old records ...................................... 3 Recording since 1993 ................................................................ 5 Presentation of data ................................................................... 6 NOTES ON SPECIES .......................................................................... 8 Introduction and abbreviations ................................................. 8 Hornworts (Anthocerotophyta) ................................................. 15 Liverworts (Marchantiophyta) ................................................. 17 Mosses (Bryophyta) ................................................................. 98 COASTAL INFLUENCES ON BRYOPHYTE DISTRIBUTION ..... 348 ANALYSIS OF CHANGES IN BRYOPHYTE DISTRIBUTION ..... 367 BIBLIOGRAPHY ................................................................................ 394 1 Acknowledgements Mrs Jean A. Paton MBE is thanked for use of records, gifts and checking of specimens, teaching me to identify liverworts, and expertise freely shared. Records have been used from the Biological Records Centre (Wallingford): thanks are due to Dr M.O. Hill and Dr C.D. Preston for providing these. Dr C.N. French and P. McCartney made records available from the ERICA Database of the former Cornish Biological Records Unit and latterly from ERCCIS. The following kindly provided information on bryophytes recorded since 1992: S. Adams, Dr J.W. Bates, I. Bennallick, J. Blackburn, T.L. Blockeel, S.D.S. Bosanquet, Dr D. Callaghan, Mrs K.M. Cocking, S. Davey, Prof. J.G. Duckett, Dr S.R. Edwards, the late Dr R.A. Finch, R.J. Fisk, Dr P.A. Gainey, Miss J.I. Hendey, Dr M.O. Hill, N.G. Hodgetts, F.R. Jeffrey, F.R. Lammiman, M. Lawley, H.W. Matcham, Miss R.J. Murphy, Ms C.J. Neil, Dr M.E. Newton, Dr S.V. O'Leary, Mrs J.A. Paton, A.R. Perry, M. Pool, R.D. Porley, Dr C.D. Preston, K. Preston-Mafham, Dr M.C.F. Proctor, Mrs C.S. Rieser, the late Dr F. Rose, Dr F.J. Rumsey, N. de Sausmarez, Dr J.D. Sleath, G. Smith, R.C. Stern, N.F. Stewart, C.C. Townsend, M.A. Walton, Ms B. Wheeler, D. Wrench. Thanks are due to the following experts for critical comments on specimens: T.H. Blackstock, T.L. Blockeel, S.D.S. Bosanquet, the late A.C. Crundwell, Dr L. Hedenäs, Dr M.O. Hill, Mrs J.A. Paton, G.P. Rothero, A.C. Smith, Dr A.J.E. Smith, C.C. Townsend, the late Dr E.V. Watson, the late Dr H.L.K. Whitehouse. Other help and miscellaneous information was received from: Mrs S. Board, Dr M.A.S. Burton, R. Clements, Prof. J.G. Duckett, Dr C.N. French, Dr M.O. Hill, N.G. Hodgetts, Miss R.J. Murphy, R.D. Porley, S. Rouen, Dr F.J. Rumsey, Dr B. Shaw, Dr A.J.E. Smith, M. Sullivan, Ms B. Tonkin, L. Walsh, the late Dr H.L.K. Whitehouse. Mrs S.M. Turk is thanked for introducing me to the County of Cornwall Reference of Place Names and other help and encouragement. Photographs that accompany the Flora were kindly made available by Dr D. Callaghan (Cephaloziella integerrima, Conardia compacta, Riccia bifurca, Telaranea europaea, Tortula wilsonii) and Dr S.R. Edwards (Douinia ovata, two photos of Cyclodictyon laetevirens); they retain the copyright. Loans of specimens are gratefully acknowledged from BBSUK, CGE, E, Isles of Scilly Museum (Hugh Town) and NMW. Other material was examined at BM, S, TRU and the Isles of Scilly Museum (Hugh Town). Grateful acknowledgement is made for funding for various of my bryological surveys in Cornwall from: former Cornish Biological Records Unit, Cornwall Environmental Consultants, Cornwall Wildlife Trust, English Nature/Natural England, Environment Agency, IMERYS, The National Trust, Plantlife/Plantlife International. Permission for access to land was freely given by numerous landowners, including Goonvean Ltd and IMERYS. Geraldine Holyoak is thanked for much encouragement, assistance and forbearance during all the years since 1993 when this project has dominated our household. 2 INTRODUCTION Scope and aims This Flora attempts to give a comprehensive account of bryophytes (mosses, liverworts and hornworts) in Cornwall and the Isles of Scilly. Its predecessor, A Bryophyte Flora of Cornwall by Jean A. Paton (1969a), was a model study combining detailed fieldwork carried out by its author throughout the 1960s with critical reappraisal of almost all significant older herbarium specimens and literature. The present work builds on the good foundations provided by Mrs Paton, presenting results of intensive new field surveys I have carried out during 1993-2010 along with comparisons of the results of these with the data from the 1960s and earlier. The new data have been assembled by mapping in the 2 × 2 km squares of the National Grid (tetrads). To allow detailed comparisons, the older records have been extensively reviewed and these too are assigned to tetrads and mapped. Coverage and treatment of old records The species accounts in this Flora assign records to three date-classes: 1791-1949 (Very old), 1950-1992 (Old), and 1993-2010 (Recent). The break at the end of 1949 corresponds to the treatment of date-classes for the national bryophyte Atlas (Hill et al. 1991-1994). The 1950-1992 date-class covers the large majority of Mrs Paton's extensive fieldwork in Cornwall which began in earnest in 1960, and also the period over which she most actively checked and assembled records made by other bryologists visiting Cornwall. The latest period corresponds to my own fieldwork, which began soon after we moved to Cornwall in 1993 and largely ended after we moved to Portugal in 2009; my records here were therefore all made after publication of the first national bryophyte Atlas. The reader is referred to Paton (1969a: 680-684) for an historical survey of bryology and bryologists in Cornwall. The earliest known records of bryophytes in Cornwall result from a few liverworts collected by E. Forster in 1791 (in BM), while the earliest moss specimens were collected by J.S. Tozer between 1820 and 1830 (in RAMM). The first systematic publications on Cornish bryophytes (Curnow 1843, Greenwood 1844, 1846) were followed during later decades of the nineteenth century by considerable bryological activity, especially by W. Curnow and J. Ralfs based in Penzance, with contributions elsewhere mainly by F. Brent, E.M. Holmes and R.V. Tellam (see Bibliography). Nevertheless, by the end of the nineteenth century the neighbourhood of Penzance and much of the Land's End Peninsula were the only districts in Cornwall that had been really well explored for bryophytes. Detailed studies on the Lizard peninsula and around St Ives only began in earnest with W.E. Nicholson's skilled work from about 1916 onwards. Many other regions remained poorly studied throughout the first half of the twentieth century, although F. Rilstone worked first in the Fowey-Perranporth-Looe region then between Newquay and Redruth. However, much of Bodmin Moor and large areas elsewhere did not receive much bryological study until Mrs Paton covered all 10-km squares (hectads) of Cornwall and the Isles of Scilly during the 1960s. Only limited use can be made of the nineteenth century bryophyte records and indeed all the pre-1950 records for comparisons with modern data. This is partly because of the patchy geographical coverage of the old records, but also because they were based on taxonomic treatments of species that have since often changed radically, and errors of identification 3 were also common. Hence it is only those old records supported by voucher specimens that were used by Paton (1969a) and in the national bryophyte Atlas (Hill et al. 1991-1994). This sceptical tradition is maintained here. The Flora by Paton (1969a) was a condensed version of a much longer 'Typescript Flora' that gave fuller details of old records. The latter typescript has been used as a starting point in assembling old records for the present work, followed by searches for additional records using the full database of Cornish and Scilly records used for the national Atlas (43720 records in all: kindly made available from the Biological Records Centre, Wallingford [BRC]), and other literature. These sources mainly listed records of rare or uncommon species, along with the first records for species in each vice-county, and a selection of records for commoner species. All of the records have been reappraised for the present study, so that known errors and a small proportion of apparently dubious records have been removed; the original specimens have also been loaned for checking of numerous identifications which seemed doubtful. The preponderance of records of rare and notable species in the pre-1950 data remains, such that really common species such as Kindbergia praelonga or Rhynchostegium confertum are badly under-represented. However, little useful purpose would be served by spending many weeks checking the old herbarium material for the common species, since many of their recorded localities are vague and the geographical coverage is anyway very patchy. Recording of bryophytes using squares of the National Grid began in the early 1960s. Localities for records from before then have been assigned to tetrads and included in the present study only when: (a) the