PROGRESS IN THE STUDY OF THE BRITISH FLORA BEING THE REPORT OF THE . CONFERENCE HELD IN 1956 BY THE BOTANICAL SOCIETY OF THE BRITISH ISLES ANBRé LAWALRfiE EDITED BY J. E. LOUSLEY 1957 Published by THE BOTANICAL SOCIETY OF THE BRITISH ISLES, c/o DEPARTMENT OF BOTANY, BRITISH MUSEUM (NATURAL HISTORY), CROMWELL ROAD, LONDON, S.W.7. Sold by the Botanical Society of the British Isles, c/o Department of Botany, British Museum (Natural History), Cromwell Road, London, S.W.7. Printed by T. BUNCLE & Co. LTD., Market Place, Arbroath. MADE IN GREAT BRITAIN. CONTENTS Page Editorial Note 7 Conference Programme ... ... ... ... ... 8 List of Members and Guests who attended the Conference 10 Introductory Remarks. T. G. TUTLN ... ... ... 11 The Early Development of a Knowledge of the British Flora. C. E. RAVEN ... <0 HHo33 13 The Contribution of Exchange Clubs to Knowledge of the British Flora. J. E. LOTJSLEY S-W^S/- ... 19 The Place of the Local Flora in the Study oijhe British Flora, J. G. DONY ... 30 The Progress of the Biological Flora. P. W. RICHARDS ... 40^ ^o36 Some Aspects of Plant Variation: The Grasses. KEITH JONES ö tto03..'f"* 45 The Importance of Experimental Ecology to the Study pi the British Flora. F. H. WHITEHEAD WOO*. 56 The Importance of the Study of Disjunct Distributions to Progress in Understanding the British Flora. FRANCIS ROSE .'© H^Cf^. 61 Development of Knowledge of the British Flora in Relation q to North Temperate Floras. D. H. VALENTINE I^U^O^ 79 Distribution Maps of Plants—An^Historical Survey. S. M. WALTERS O^OW'i 89 The Status of Viola lactea (Exhibit). D. M. MOORE ^^0^-^97 Natural Hybridization of Agrostis stolonifera and A, tenuis (Exhibit). A. D. BRADSHAW ... 103 Alchemilla vulgaris L. agg. in Britain ^Exhibit). Miss M. E. BRADSHAW J6 W-O^S' 106 EDITORIAL NOTE Study of the British flora has made outstanding progress during the past decade and this is therefore an appropriate time to review the methods employed and to consider the most favourable lines for development. The fifth conference sponsored by the Botanical Society of the British Isles was arranged with this object. Consideration of old techniques brought out aspects which have been neglected or misunderstood; accounts of modern methods were illustrated by examples of current work; the review presented an overall picture of available methods which those present at the Conference were able to apply to their own lines of research. The papers and discussion brought out in the clearest possible way two broad lines of development which offer the greatest promise at the present time (see page 124). All the papers read and the accounts of exhibits are published in this book together with the discussion. They are arranged in the sequence used at the Conference except that the exhibits are brought together after the main papers. The scientific names are those used by the speakers except that all trivials are spelled with an initial small letter in accordance with the general policy of the Society. The arrangements for the Conference were in the hands of the Meetings Committee of the Society. Much of the work fell on Dr. J. G. Dony, then Honorary Meetings Secretary, and to his energy and enthusiasm, together with that of the other members of the Committee, and other officers and members who assisted, the success of the Conference was due. I am grateful to J. P. M. Brenan, D. H. Kent, N. Y. Sandwith, Dr. S. M. Walters, P. J. Wanstall, and Dr. E. P. Warburg, members of the Society's Publications Committee, and to E. B. Bangerter for assistance in proof reading. J. E. LOUSLEY. 8 CONFERENCE PROGRAMME PROGRESS IN THE STUDY OF THE BRITISH FLORA FRIDAY, April 13th 10.15 a.m. A welcome to the Conference Prof. T. G. TUTIN 10.30 The early development of a knowledge of the British flora Rev. Canon 0. E. RAVEN 11.30 The Eighteenth and Nineteenth Century background to the study of the British flora Dr. G. TAYLOR 12.15 p.m. Interval for luncheon 2.00 The contribution of the Exchange Clubs to knowledge of the British flora Mr. J. E. LOTTSLEY 2.45 The place of the local Flora in the study of the British flora Dr. J. G. DONY 3.30 Interval 3.45 The progress of the Biological Flora Prof. P. W. RICHARDS 4.30 Interval for tea 5.30 EXHIBITION MEETING Exhibits will be displayed in the Botany Department, close to Tuke Hall, and may be seen at any time during the period of the Conference. During the evening exhibitors will explain their exhibits and answer questions regarding them in Tuke Hall. 6.00 p.m. The status of Viola, lactea Sm. Mr. D. M. MOORE 6.15 Natural Selection in favour of the hybrid Agrostis stoloni- fera X tenuis Mr. A. D. BBADSHAW 6.30 Alchemilla vulgaris L. agg. in Britain Miss M. E. BBADSHAW 6.45 A comparison of the spread of Galinsoga parviflora and G. ciliata Dr. W. S. LACET 9 7.00 The Species Problem in Galium pwrnvlum Mr. K. M. GOODWAY 7.15 Variation and distribution in Erica maclcaiana Bab. Mr. P. A. GAY SATURDAY, April 14th 10.15 a.m.—Some aspects of plant variation—the Grasses Mr. K. JONES 11.00 The importance of Experimental Ecology in the study of the British flora Dr. F. H. WHITEHEAD 11.45 Interval 11.55 The importance of relict and disjunct distributions in the interpretation of the history of the present British flora Dr. P. ROSE 12.45 p.m. Interval for luncheon 2.30 Distribution Maps of plants—an historical survey Dr. S. M. WALTERS 3.30 The study of our flora as a part of a whole Prof. D. H. VALENTINE 4.30 Concluding remarks by the President 4.45 Close of conference SUNDAY, April 15th FIELD MEETING IN THE NEIGHBOURHOOD OF HITCHIN. HERTFORDSHIRE The programme printed above is as circulated before the Conference. It was carried out as stated, except that the President, Dr. George Taylor, was unable to be present. As he was also unable to prepare his paper, Canon C. E. Raven kindly expanded his account of "The Early Development of a Know­ ledge of the British Flora" into the time allowed for Dr. Taylor's paper in the programme. The proceedings on the second day were closed by Professor T. G. Tutin. 10 LIST OF MEMBERS AND GUESTS WHO ATTENDED THE CONFERENCE, April 13 and 14, 1956 D. E. Allen, Miss M. C. Allott, Dr. K. L. Alvin. P. W. Ball, P. D. W. Barnard, Miss F. M. Barton, Mrs. D. L. Bennett, Miss D. Bexon, R. A. Blakelock, Miss I. Blewitt, Dr. H. J. M. Bowen, A. D. Bradshaw, Miss M. E. Bradshaw, G. M. Brown, Miss J. Buchanan, Miss K. I. Butler. Miss D. A. Cadbury, J. F. M. and Mrs. Cannon, A. J. Carpenter, Miss S. Carter, K. E. Cockshull, T. G. Collett, Miss A. Conolly, A. Cridland. Mrs. H. E. Davies, Miss 0. R. Dewey, Dr. J. G. Dony, D. Dupree. T. R. Eagles, D. St.J. Ecclestone, Rev. E. A. Elliot, Dr. A. G. Erith. R. S. R. Fitter. P. B. Gahan, P. A. and Mrs. Gay, Miss E. J. Gibbons, Mrs. A. N. Gibby, J. L. Gilbert, J. B. Gillett, D. R. Glendinning, W. J. Göddard. Miss C. M. Goodman, K. M. Goodway, R. A. Graham, Miss M. Gregory, P. Greig-Smith, H. C. Grigg, E. W. Groves. P. C. and Mrs. Hall, Miss Halliday, D. E. Hardy, R, Harley, Miss Harvey, Dr. J, G. Hawkes, J. H. Hemsley, F. N. Hepper, T. F. Hering, Miss S. S. Hooper, Miss M. A. Hudson, Mrs. B. A. Hulme. Miss M. Isaac, Miss E. M. C. Isherwood. L. James, A. C. Jermy, Miss H. Jenkins, K. Jones. D. H. Kent, Miss M. P. H. Kertland. Dr. W. S. Lacey, Dr. J. M. Lambert, J. Latham, W. N. and Mrs. Lawfield, G. F. Lawrence, Dr. V. E. Lloyd, Dr. L. Lloyd-Evans, Miss C. Longfield, J. E. Löusley. D. McClintock, P. H. McNally, R, D. Meikle, Dr. A. Melderis, Dr. R. Melville, B. Miles, R. Minor, M. S. Moon, D. M. Moore, Miss B. M. C. Morgan. P. J. and Mrs. Newbould, P. M. Newey. Miss W. T. M. O'Connor. Mrs. A. T. Peppercorn, F. H. Perring, D. W. Pickering, D. L. H. Porter, T. F. Preece, Dr. C. T. Prime, Miss E. A. Pringle, N. M. Pritchard. J. A. Ratter, Canon C. E. Raven, Miss Rawlins, R, C. Readett, B. W. Ribbons, Mrs. M. Richards, Prof. P. W. Richards, Dr. R. Riley, Miss M. F. Roberts, C. A. Robinson, N. K. B. Robson, Dr. F. Rose, M. D. Ross, Dr. E. M. Rosser, J. Rossiter, Mrs. B. H. S, Russell. R. E. and Mrs. Sandell, Miss M. Sands, N. Y. Sandwith, Mrs. N. Saunders, J. P. Savidge, D. Schofield, Miss M. Scholey, P. D. Sell, Miss E. Shaw, K. C. and Mrs. Side, Dr. E. Smithson, J. L. Southern, Miss J. Stevens. R. F. Turney, Prof. T. G. Tütin. Prof. D. H. Valentine, Miss D. E. de Vesian, Miss B. M. Vizard Dr. S, M. Walters, P. J. Wanstall, Dr. E. F. Warburg, W. E. Warren, Mrs. W. Boyd Watt, Mrs. B. Welch, Dr. C. West, A. W. Westrup, Dr. F. H. Whitehead, Mks M. M. Whiting, J. E. Willé, Miss A. F. Wood, S. R. J. Woodell, J. E, Woodhead. P. F. Yeo, Dr. D. P. Young. INTRODUCTORY REMARKS 11 INTRODUCTORY REMARKS The Conference was opened by Professor T.