562 TRANSACTIONS OF SECTION K. 



British ecologists have combined to attack a series of the problems from very 

 diverse points of view leads one to hope that, with a continuance of that inti- 

 mate co-operation which has characterised their work so far, and with the added 

 stimulus of the friendly visit of our distinguished colleagues from abroad, con- 

 siderable progress may be expected in the future in this branch of botanical 

 study. Privileged as I have been to assist at the deliberations of the British 

 ecologists, without as yet having taken any active part in their work, I feel 

 myself at liberty to point with appreciation to the excellent beginning they have 

 made of a botanical survey of Great Britain and Ireland, as well as to the more 

 detailed investigations of special associations and formations, such as the wood- 

 lands, the moorlands, the fens, the broads, salt marshes, and shingle beaches. I 

 am glad to think that our foreign visitors have been able to see these interesting 

 types of vegetation under the guidance of those who have made a special study 

 of these subjects. 



The importance to ecologists of an up-to-date critical Flora was dwelt upon 

 by my predecessor in this presidential chair, and this obvious need may be re- 

 garded as a further illustration of the inter-relationship of the various aspects 

 of Botanical Science. Though it has been obvious to all that the swing of the 

 pendulum has been for a long time away from pure systematic botany, I am con- 

 vinced that the great development of plant ecology, of which we have many 

 indications, will not merely lessen the momentum of the swinging pendulum, but 

 will draw the latter back towards a renewed and critical study of the British 

 flora. That a revival of interest in systematic botany will come through the 

 labours of those who are engaged in survey work and other forms of ecological 

 study, is foreshadowed by the fact that Dr. Moss has undertaken to edit a ' New 

 British Flora,' which will, I believe, largely fulfil the objects put forward by 

 Professor Trail in his Presidential Address. I trust, however, that in addition 

 to the ecologists, those botanists who are interested in genetics will contribute 

 their share towards the completion of our knowledge of critical species, varieties, 

 and hybrids, all of which offer such intricate problems alike to the systematist 

 and to the student of genetics. 



De Vries prefaced his lectures on ' Species and Varieties, their Origin by 

 Mutation,' by the pregnant sentence : ' The origin of species is an object of ex- 

 perimental investigation,' and this is equally true of the study of the real and 

 presumptive hybrids of our British flora, which may be investigated either syn- 

 thetically or, when fertile, also analytically, as in some cases their offspring show 

 striking Mendelian segregation. Some good work has already been accomplished 

 in this direction, but more remains to be done, and we have here an important 

 and useful sphere of work for the energies of many skilled plant-breeders. 



I would, therefore, like to plead for intimate collaboration between all 

 botanists, hopeful that, as progress in the past has come through the labours of 

 men of wide sympathies, so in the future, when studies are bound to become more 

 specialised, there will be no narrowing of interests, but that the various prob- 

 lems which have to be solved will be attacked from all points of view, the mor- 

 phological, the physiological, the ecological, and the systematic. Thus by united 

 efforts and close co-operation of botanists of all schools and of all countries we 

 shall gain the power to surmount the difficulties with which our science is still 

 confronted. 



The following Papers were read : — 



1. The Life-History of a Shingle Bank. 

 By Professor F. W. Oliver, F.R.S. 



This communication dealt with the conditions under which plants exist on 

 accumulations of maritime shingle reaching above spring-tide limits. The locali- 

 ties studied include the following shingle-banks : Blakeney, Chesfl, Hurst Castle, 

 Calshot, Hamstead Dover (Isle of Wight), and Rye. 



The first point to be emphasised is the mobility of most shingle banks, 

 resulting in a landward creep of the bank as a whole. This lateral movement 

 is promoted by two distinct but related processes. (1) By the direct action 

 of storm waves which lifts the shingle over the crest and scatters it down 



