322 



THE GABDENEBS' CHBONIGLE. 



[September 22, 1888. 



completed the theory of the flower. In the follow- 

 ing century Morison first raised Terns from spores, 

 Lindsay detected the Fern prothallus, Ray laid the 

 foundations of a natural classification, Hales disco- 

 vered root-pressure, and Priestley the absorption of 

 carbon dioxide and the evolution of oxygen by 

 plants. In the early part of the present one we have 

 Knight's discovery of the true cause of geotropism, 

 Daubeny's of the effect upon the processes of plant- 

 life of rays of light of different refrangibility ; and 

 finally, the first description of the cell-nucleus by R. 

 Brown. I have singled out these disceveries as strik- 

 ing landmarks, the starting-points of important deve- 

 lopments of the subject. It is enough for my purpose 

 t ) show that we have always had an important school 

 of botany in England, which has contributed at least 

 its share to the general development of the science. 



Systematic Botany. 



" As the head of one of the great national esta- 

 blishments of the country devoted to the cultivation 

 of systematic botany, I need hardly apologise for de- 

 voting a few words to the present position of that 

 branch of the science. Of its fundamental import- 

 ance I have myself no manner of doubt. But as my 

 judgment may seem in such a matter not wholly free 

 from bias, I may fortify myself with an opinion 

 which can "hardly 'be minimised in that way. The 

 distinguished chemist, Professor Lothar Meyer, 

 perhaps the most brilliant worker in the field of 

 theoretical chemistry, finds himself, like the sys- 

 tematic botanist, obliged to defend the position of 

 descriptive science. And he draws his strongest 

 argument from biology. ' The physiology of plants 

 and animals,' he tells us, ' requires systematic botany 

 and zoology, together with the anatomy of the two 

 kingdoms : each speculative science requires a rich 

 and well-ordered material, if it is not to lose itself 

 in empty and fruitless fantasies.' No one, of course, 

 supposes that the accumulation of plant specimens 

 iu herbaria is the mere outcome of a passion for 

 accumulating. But to do good systematic work 

 requires high qualities of exactitude, patience, and 

 judgment. As I had occasion to show at the Lin- 

 nean Centenary, the world is hardly sensible of the 

 inluence which the study of the subject has had on 

 i.s affairs. The school of Jeremy Bentham has left 

 an indelible mark on the social and legislative pro- 

 gress of our own time. Mill tells us that ' the 

 proper arrangement of a code of laws depends on the 

 same scientific conditions as the classifications in 

 natural history ; nor could there,' he adds, ' be a 

 better preparatory discipline for that important 

 function than the principles of a natural arrange- 

 ment, not only in the abstract, but in their actual 

 application to the class of phenomena for which they 

 were first elaborated, and which are still the best 

 school for learning their use.' He further tells us 

 that of this Jeremy Bentham was perfectly aware, 

 and that his Fragment on Government contains clear 

 and just views on the meaning of a natural arrange- 

 ment which reflect directly the influence of Linnteus 

 and Jussieu. Mill himself possessed a competent 

 knowledge of systematic botany, and therefore was 

 well able to judge of its intellectual value. Por my 

 p irt, I do not doubt that precisely the same qualifi- 

 c itions of mind which made Jeremy Bentham a 

 great jurist enabled his nephew to attain the emi- 

 nence he reached as a botanist. As a mere matter 

 o ' mental gymnastics, taxonomic science will hold its 

 o vn with any pursuit. And, of course, what I say 

 of botany is no less true of other branches of natural 

 history. Mr. Darwin devoted eight or nine years to 

 the systematic study of the Cirripedia. ' No one,' 

 he himself tells us, 'has a right to examine the 

 qiestion of species who has not minutely described 

 many.' And Mr. Huxley has pointed out, in the 

 admirable memoir of Mr. Darwin which he has pre- 

 pa ed for the Royal Society, that the acquirement of 

 an intimate and practical knowledge of the process 

 of species-making . . .' was ' of no less importance to 

 the author of the Origin of Species than was the 

 bearing of the Cirripede work upon tie principles of 

 a natural classification.' 



" At present, undoubtedly, the younger generation 

 of botanists show a disposition to turn aside to those 

 fields in which more brilliant and more immediate 

 result.can be attained. Their neglect of systematic 

 b >tany brings to some extent its own Nemesis. A 

 iirs,t principle of systematic botany is that a name 

 should denote a definite and ascertainable species of 

 ptanr. But in physiological literature you will find 



that the importance of this is entirely overlooked. 

 Names are employed which are either not to be found 

 in the books, or they are altogether misapplied. But 

 if proper precautions be taken to ascertain the 

 accurate botanical name of a plant, no botanist 

 throughout the civilised world is at a loss to identify 

 it. But precision in nomenclature is only the neces- 

 sary apparatus of the subject. The data of systematic 

 botany, when properly discussed, lend themselves to 

 very important generalisations. 



Geographical Distribution. 

 "Perhaps those which are yielded by the study 

 of geographical distribution are of the most 

 general interest. The mantle of vegetation 

 which covers 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 distribution of land and sea. 

 Here, however, we are embarassed 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. Everywhere the 

 primitive vegetation is disappearing as more and 

 more of the earth's surface is brought into cultiva- 

 tion, 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 

 Perdinand Mueller a comprehensive flora of Aus- 

 tralia, 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 botanieally 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 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 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 

 committee has been practically limited to Central 

 and Eastern China. Prom the west, in Yunnan, 

 the French botanists have received even more sur- 

 prising collections, and these supplement our own 

 work in the most fortunate manner. I have only to 

 add for Asia Boissier's Mora Orienfalis, which prac- 

 tically 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 ade- 

 quately 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 Kilima-Njaro 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, investi- 

 gated by Mr. Baker, is perhaps at the moment the 

 most interesting problem which Africa presents to 

 the botanists. The flora as a whole presents a large 

 proportion of endemic genera and 6pecies, pointing 

 to isolation from a very ancient date. The tropical 

 element is, however, closely allied to that of Tropical 

 Africa and of the Mascerene 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 the temperate 

 flora, the ruins of which are scattered orer the 

 mountainous regions of Central Africa, and which 



survives in its greatest concentration at the Cape. 

 The American botanists at Harvard are still syste- 

 matically carrying on the work of Torrey and Gray 

 in the elaboration of the flora of Northern 

 America. The Russians are, on their part, con- 

 tinually adding to our knowledge of the flora of 

 Northern and Central Asia. The whole flora of 

 the north temperate zone can only be regarded sub- 

 stantially as one. The identity diminishes south- 

 wards, 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 publica- 

 tion of the results. I am happy to say that the 

 botanical portion, which has been elaborated at Kew, 

 is all but finished. In South America I must con- 

 tent myself with referring to the great Flora Brasi- 

 liensis, commenced by Martius half a century ago, 

 and still slowly progressing under the editorship of 

 Professor Urban at Berlin. The travels of Mr. 

 Ball in South America have led him to the detec- 

 tion of some very interesting problems. The enor- 

 mous pluvial denudation of the ancient portions of 

 the continent 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 admix- 

 ture of modified temperate types, which gives to the 

 whole a peculiar character not met with to the same 

 degree in the tropics of the whole 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 elaborated at Kew, brought for the first 

 time into one view 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 

 Mosely and supplemented by the notes and specimens 

 accumulated with much judgment by Dr. Guppy. 

 Por 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 exami- 

 nation 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 con- 

 geners from Java, but yet do not differ sufficiently 

 to be specifically distinguished. We have here, 

 therefore, it appears to me, a manifest case of 

 nascent species. 



Classification. 



" The central problem of systematic botany is to per- 

 fect 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 ex- 

 perience 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 pro- 

 cesses. Upon these, indeed, the correct classification 

 of the vascular cryptogams wholly depends, and 

 generally, as we descend in the scale, external mor- 

 phology becomes more and more insecure as a guide, 

 and a thorough knowledge of the minute structure 

 and life history of each organism becomes indis- 

 pensable 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 lichenologist?. 

 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 classifica-. 

 tion had been firmly grasped. This leads me to 



