TRANSACTIONS OF SECTION D. 689 



geographical distribution are of the most general interest. The mantle of vegeta- 

 tion which covers the surface of the earth, if only we could rightly unravel 

 its texture, would tell us a good deal about geological historJ^ The study of 

 geographical distribution, properly handled, aflbrds an independent line of attack 

 upon the problem of the past distribution of land and sea. It would probably 

 never afford sufficient data for a complete independent solution of the problem ; 

 but it must always be extremely useful as a check upon other methods. Here, 

 however, we are embarrassed by the enormous amount of work which has yet to 

 be accomplished. And unfortunately this is not of a kind which can be indefinitely 

 postponed. The old terrestrial order is fast passing away before our eyes. Every- 

 where the primitive vegetation is disappearing as more and more of the earth's 

 surface is brought into cultivation or, at any rate, denuded of its forests. 



A good deal, however, has been done. We owe to the indomitable industry of Mr. 

 Bentham and of Sir Ferdinand Mueller a comprehensive flora of Australia, the first 

 large area of the earth's surface of which the vegetation has been completely worked 

 out. Sir Joseph Hooker, in his retirement, has pushed on within sight of com- 

 pletion the enormous work of describing so much of the vast Indo-Malayan flora as 

 is comprised within British possessions. To the Dutch botanists we owe a tolerably 

 complete account of the Malayan flora proper. But New Guinea still remains 

 botanically a terra incognita, and tiU within the last year or two the flora of China 

 has been an absolute blank to us. A committee of the British Association (whose 

 report will be presented to you) has, with the aid of a small grant of money, taken 

 in hand the task of gathering up the scanty data which are a%'ailable in herbaria 

 and elsewhere. This has stimulated European residents in China to collect more 

 material, and the fine collections which are now being rapidly poured in upon us 

 will, if they do not overwhelm us by their very magnitude, go a long way ia 

 supplying data for a tentative discussion of the relations of the Chinese flora to 

 that of the rest of Asia. I do not doubt that this will in turn explain a good deal 

 that is anomalous in the distribution of plants in India. The work of the com- 

 mittee has been practically limited to Central and Eastern China. From the west, 

 in Yunnan, the French botanists have received even more surprising collections, and 

 these supplement our own work in the most fortunate manner. I have only to add 

 for Asia Boissier's ' Flora Orientalis,' which practically includes the Mediterranean 

 basin. But I must not omit the invaluable report of Brigade-Surgeon Aitchison 

 on the collections made by him during the Afghan Delimitation Expedition. This 

 has given an important insight into the vegetation of a region which had never 

 previously been adequately examined. Nor must I forget the recent publication of 

 the masterly report by Professor Bayley Balfour on the plants collected by himself 

 and Schweinfurth in Socotra, an island with which the ancient Egyptians traded, but 

 the singularly anomalous flora of which was almost wholly unknown up to our 

 time. 



The flora of Africa has been at present but imperfectly worked up, but the 

 materials have been so far discussed as to afford a tolerably correct theory of its 

 relations. The harvest from Mr. Johnston's expedition to KUmanjaro was not as 

 rich as might have been hoped. Still, it was sufficient to confirm the conclusions 

 at which Sir Joseph Hooker had arrived, on very slender data, as to the relations 

 of the high-level vegetation of Africa generally. The flora of Madagascar is perhaps, 

 at the moment, the most interesting problem which Africa presents to the botanist. 

 As the rich collections, for which we are indebted to Mr. Baron and others, are 

 gradually worked out, it can hardly be doubted that it will be necessary to modify 

 in some respects the views which are generally received as to the relation of the 

 island to the African continent. My colleague, Mr. Baker, communicated to the 

 York Meeting of the Association the results which, up to that time, he had arrived 

 at, and these subsequent material has not led him to modify. The flora as a whole 

 presents a large proportion of endemic genera and species, pointing to isolation 

 from a very ancient date. The tropical element is, however, closely allied to that 

 of Tropical Africa and of the Mascarene Islands, and there is a small infusion of 

 Asiatic types which do not extend to Africa. The high-level flora, on the other 

 hand, exhibits an even closer affinity with that temperate flora the ruins of which 



1888. Y Y 



