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SCIENTIFIC NEWS. 



[Sept. 7, iS 



But precision in nomenclature is only the necessary apparatus of 

 the subject. The data of systematic botany, when properly dis- 

 discussed, lend themselves to very important generalisations. Per- 

 haps those which are yielded by the study of geographical distribu- 

 tion are of the most general interest. The mantle of vegetation 

 which coveis the surface of the earth, if only we could rightly 

 unravel its texture, would tell us a good deal about geological 

 history. The study of geographical distribution, rightly handled, 

 affords an independent line of attack upon the problem of the past 

 distribulion of land and sea. It would probably never afford suffi- 

 cient 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 terres- 

 trial order is fast passing away before our eyes. Everywhere 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 indomit- 

 able industry of Mr. Bentham and of Sir Ferdinand Mueller a com- 

 prehensive 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 

 completion 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 till 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 available 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 in supplying data for a ten'a- 

 tive 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 committee has been practically limi ed to Central and 

 Eastern China. From the west, in Yunnan, the French botanists 

 have received even more surprising collections, and these supple- 

 ment our own work in the most fortunate manner. I have only to 

 add for Asia Boissier's "Flora Orientalis," which practically in- 

 cludes 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 Bal- 

 four on the plants collected by himself and Schweinfurth in Socotra, 

 an island with which the ancient Egyptians traded, but the singu- 

 larly 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 Kilimanjaro 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 col- 

 lections 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 materialshad 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 tropi- 

 cal 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 tem- 

 perate flora the ruins of which are scattered over the mountainous 

 regions of Central Africa, and which survives in its greatest concen- 

 tration at the Cape. 



The American botanists at Harvard are still systematically carry- 

 ing on the work of Torrey and Gray in the elaboration of the flora 

 of Northern America. The Russians are, on their part, continually 



adding to our knowledge of the flora of Northern and Central Asia. 

 The whole flora of the North Temperate Zone can only be regarded 

 substantially as one. The identity diminishes southwards, and 

 increases in the case of the Arctic and Alpine regions. A collection 

 of plants brought us from high levels in Corea by Mr. James might, 

 as regards a large proportion of the species, have been gathered on 

 one of our own Scotch hills. 



We owe to the munificence of two English men of science the 

 organisation of an extensive examination of the flora and fauna of 

 Central America and the publication of the results. The work, 

 when completed, can hardly be less expensive than that of the results 

 of the Challenger voyage, which has severely taxed the liberality 

 of the English Government. The problems which geographical 

 distribution in this region present will doubtless be found to be of a 

 singularly complicated nature, and it is impossible to over-estimate 

 the debt of gratitude which biologists of all countries must owe to 

 Messrs. Godman and Salvin, when their arduous undertaking is 

 completed. I am happy to say that the botanical portion, which 

 has been elaborated at Kew, is all but finished. 



In South America I must content myself with referring to the 

 great ". Flora Brasiliensis," commenced by Martius half a century 

 ago, and still slowly progressing under the editorship of Professor 

 Urban at Berlin. Little discussion has yet been attempted of the 

 mass of material which is enshrined in the mighty array of volumes 

 already published. But the travels of Mr. Ball in South America 

 have led him to the detection of some very interesting problems. 

 The enormous pluvial denudation of the ancient portions of the con- 

 tinent has led to the gradual blending of the flora of different levels 

 with sufficient slowness to permit of adaptive changes in the process. 

 The tropical flora of Brazil, therefore, presents an admixture of 

 modified temperate types which gives to the whole a peculiar 

 character not met with to the same degree in the tropics of the 

 old world. On the other hand, the comparatively recent elevation 

 of the southern portion of the continent accounts, in Mr. Ball's 

 eyes, for the singular poverty of its flora, which we may regard, 

 indeed, as still in progress of development. 



The botany of the Challenger expedition, which was also elabo- 

 rated at Kew, brought for the first time into one vie* all the 

 available facts as to the floras of the older oceanic islands. To this 

 was added a discussion of the origin of the more recent floras of the 

 islands of the Western Pacific, based upon material carefully collected 

 by Professor Moseley, and supplemented by the notes and specimens 

 accumulated with much judgment by Dr. Guppy. For the first 

 time we were enabled to get some idea how a tropical island was 

 furnished with plants, and to discriminate the littoral element due to 

 the action of oceanic currents from the interior forest almost wholly 

 due to frugivorous birds. The recent examination of Christmas 

 Island by the English Admiralty has shown the process of island 

 flora-making in another stage. The plants collected by Mr. Lister 

 prove, as might be expected, to be closely allied to those of Java. 

 But the effect of isolation has begun to tell ; and I learn from my 

 colleague Professor Oliver that the plants from Christmas Island 

 cannot be for the most part exactly matched with their congeners 

 from Java, but yet do not differ sufficiently to be specifically distin- 

 guished. We have here, therefore, it appears to me, a manifest case 

 of nascent species. 



The central problem of systematic botany I have not as yet 

 touched upon : this is to perfect a natural classification. Such a 

 classification, to be perfect, must be the ultimate generalisation of 

 every scrap of knowledge which we can bring to bear upon the study 

 of plant affinity. In the higher plants experience has shown that 

 we can obtain results which are sufficiently accurate for the present, 

 without carrying our structural analysis very far. Yet even here 

 the correct relations of the Gymnosperms would never have been 

 ascertained without patient and minute microscopic study of the 

 reproductive processes. Upon these, indeed, the correct classifica- 

 tion of the Vascular Cryptogams wholly depends, and generally, as 

 we descend in the scale, external morphology becomes more and 

 more insecure as a guide, and a thorough knowledge of the minute 

 structure and life history of each organism becomes indispensable 

 to anything like a correct determination of its taxonomic position. 

 The marvellous theory of the true nature of Lichens would never 

 have been ascertained by the ordinary methods of examination 

 which were held to be sufficient by lichenologists. 



The final form of every natural classification —for I have no doubt that 

 the general principles I have laid down are equally true in the field 

 of zoology— must be to approximate to the order of descent. For 

 the Theory of Descent became an irresistible induction as soon 

 as the idea of a natural classification had been firmly grasped. 



Interesting as are the problems which the structure, the functions, 

 the affinity, or the geographical distribution of a plant may afford, 

 the living plant in itself is even more interesting still. Every 

 organ will bear interrogation to trace the meaning and origin 



