PRESIDENTIAL ADDRESS. 773 



direct or by modifying habitats, as shown by Lupinus nootlatcnsis in the valleys 

 of rivers in Scotland. . , 



Those species that there is reason to regard as not having been introduced by 

 man should be investigated as regards their probable origins and the periods and 

 methods of immigration, evidence from fossil deposits of the period during which 

 they have existed in this country, their constancy or liability to show change 

 during this period, their resemblance to or differences from the types in the 

 countries from which they are believed to have been derived, or the likelihood 

 of their having originated by mutation or by slow change within the British 

 Islands, and their relation to man's influence on them (usually harmful, but 

 occasionally helpful) as affecting their distribution and permanence. _ 



The topographical distribution, though so much has been done in this field 

 during the past sixty or seventy years, still requires careful investigation, to 

 determine not merely that species have been observed in certain districts, but 

 their relative frequency, their relations to man (natives of one part of our country 

 are often aliens in other parts), whether increasing or diminishing, altitudes, 

 habitats, &c. From such a" careful topographical survey much should be learned 

 of the conditions that favour or hinder the success of species, of the evolution 

 of new forms and their relation to parent types in distribution, especially in the 

 more isolated districts and islands, and of other biological problems of great 

 interest. A most useful aid towards the preparation of topographical records 

 would be afforded by the issue at a small price of outline maps so as to allow of 

 a separate map being employed for recording the distribution of each form. 



A careful study of the flora is also required from the standpoint of structure 

 and development, with comparison of the results obtained here with those of 

 workers in other countries where the same or closely allied species and varieties 

 occur. It is also needed in respect of the relations between the plants and animals 

 of our islands, both as observed here and in comparison with the already exten- 

 sive records of a similar kind in other countries. On such topics as pollination, 

 distribution of seeds, and injuries inflicted by animals and galls produced by 

 animals or plants we have still to make use very largely of the information gained 

 abroad ; and the same holds good with regard to the diseases of plants. 



While ' English Botany ' in its first edition was deservedly regarded as a 

 work of the first rank among floras, it has long been defective as representing 

 our pi'esent knowledge of British plants, and it has not been succeeded by any 

 work of nearly equal rank, while other countries now have their great floras of a 

 type in advance of it. There is need for a great work worthy of our country, 

 amply illustrated so as to show not only the habit of the species and varieties, 

 but also the distinctive characters and the more important biological features of 

 each. Such a flora would probably require to be in the form of monographs by 

 specialists, issued as each could be prepared, but as part of a well-planned whole. 

 It should give for each plant far more than is contained in even the best of our 

 existing British floras. Means of identification must be provided in the description, 

 with emphasised diagnostic characters ; but there should also be the necessary 

 synonymy, a summary of topographical distribution, notes on man's influence upon 

 distribution, abundance, &c, on any biological or other point of interest in struc- 

 ture or relations to habitat, environment, associated animals or plants, diseases, 

 &c. Local names, uses, and folklore should also be included ; and for this the 

 need is all the greater, because much of such old lore is rapidly being forgotten 

 and tends to be lost. In a national flora there should be included an account of 

 the successive floras of former periods, and, as far as possible, the changes that 

 can be traced in the existing flora from its earliest records to tho time of issue 

 should be recorded. 



A flora of this kind would not only afford the fullest possible information with 

 regard to the plant world of the British Islands at the date of issue, but would 

 form a standard with which it could be compared at later periods, so as to permit 

 of changes in it being recognised and measured. In the meanwhile the production 

 of such a flora can be regarded only as an aim towards which to press on, but 

 which cannot be attained until much has been done. But while the fulfilment 

 must be left to others, we can do something to help it on by trying to remove 

 difficulties from the way, and to bring together materials that may be used in its 

 construction. 



I have sought to call attention 1o the difficulties that I have experienced and to 



