112 



NATURE 



[yjtnc 6, 1872 



Leaving, howeve', these qu»stions of origin aside, he strongly 

 objects to the classing representative with identical species in 

 considering geographical ilislrlliution ; for the former appear in 

 such absolutely dissevered distant regions that an interchange of 

 species, even in early geological periods, seems impossible, as, 

 for instance, in the case of several Ericas of the Cape and of 

 Europe. It is on the contrary, he believes, almost always pos- 

 sible to deduce the actual progress of identical species from the 

 form or physical accidents of their homes and from the means 

 of dispersion at their command (p. 519). He therefore, in com- 

 bating Asa Gray's conclusion, commences by eliminating from 

 his calculations, after the example of Miquel (" Over de Ver- 

 wantschap der Flora van Japan met AziiJ en Noord America, 

 Versl. K. Akad." Amsterdam, ser. 2, ii.), all representative 

 species, thus reducing Asa Gray's list of concordant races in 

 Japan and Eastern North America from 226 to Si, from these 

 Grisebach subtracts 41, which are also inhabitants of Western 

 North America, and can slill, he thinks, dady transmit their 

 seeds across the Pacific Ocean ; 17 more are, in his opinion, sup- 

 ported by that of other botanists, either certainly not identical or 

 doubtful, and to be added to ihe already eliminated representa- 

 tive species. Of the remaining 23, he finds 21 which can bear a 

 high northern climate and may yet be found in the Oregon or 

 other imperfectly explored territories of North- West America; 

 and the whole long list is thus reduced to two species only, 

 whose problematical disseverance in Japan and Eastern Nortli 

 America remains unexplained — the one, EhhLti fciiolatii, being a 

 marsh ]ilant, wliich as such possesses great migratory powers, the 

 other. Cans roslrata, from the White Mountains, awaits furtlier 

 researches on its geographical dis'rihution. Even admitting the 

 possibility of the greater early dispersion of these species in for- 

 mer geo'ogical perioils propounded by Asa Gray, Grisebach thinks 

 that any such great antiquity of the Japanese flora is not estab- 

 lished on so firm a ground as to supersede any attempts at find- 

 ing other explanaticins limited to the results of forces stUl in 

 activity in present times, and that accordingly the distribution of 

 the species in queslion may be satisfactorily accounted for by the 

 means of disper.sion still avaihible, if the data are viewed in the 

 light he has placed them. I .should doubt, however, whether his 

 mode of cutting up a long array of ascertained facts fuither in- 

 creased by subsequent researches in order to mike them agree 

 with preconceived theories, wid carry any stronger conviction 

 into Asa Gray's mind than in my own, more especially as the 

 ])resumed great antiqui: y of the Japanese flora is not deduced 

 fiom these facts alone, liut is derived also from other eviilences, 

 Amongst which the peculiar character of the endemic monot)pes 

 bears a prominent part. 



With regard to Grisebach's ilea that representative and simi- 

 lar species are independently produced by similarity of climato- 

 logical conditions, and that they afford no conclusive evidence of 

 community of origin, for that they are to be found in widely 

 dissevered localities between which it is impossible to conceive 

 any continuity even in ancient geological periods, and with refe- 

 rence to the instance he adduces of the above-mentioned heaths 

 of the Cape and of Western Europe, I would recall to your 

 minds some remarks I made in my Address of 1S69 (p. 25 ; 

 " Proceedings," p. Ixxxvii.) on the remarkable coincidence of 

 several genera, and the ntar similarity of some species that 

 exists between these two widely dissevered regions. I would 

 now add that if it is difficult to imagine any ancient continuiiy 

 which should readily explain this phenomenon, it seems equally 

 tliffijult to account for it by any climatolo^itral similarity, if we 

 consider how much Cape plants in general, accustomed to a pro- 

 longed summer's sun, suffer from its want in the dull damp sea- 

 sons of Western Europe. 



The Eastern Archipelago, the study of whose fauna, as con- 

 nected with the history of the great changes it has undergone by 

 successive submersions and upheav.als, has been rendered so in- 

 teresting by the well-known labours of Mr. K. R. Wallace, calls 

 imperatively on the attention of botanists in the search of facts 

 derived from its flora in confirmation or refutation of these views. 

 Unfortunately we are in this respect very much in arrear. The 

 botany of New Guinea is almost wholly unknown ; and from 

 Celebes we have but very little. Sumatra, Java, the Phdippines, 

 Timor, and a part of Bonie", have been more generally explored, 

 and lari;e collections of their jilants have been deposited, chiefly 

 in the Leyden Herbarium, but also in considerable numbers in 

 those of Keiv and in some others ; but even these materials have 

 been but litile worked up in a manner to be available for the 

 geographical botanist. The two eminent Dutch botanists who 



had successively charge of the Leyden collections contributed 

 much in various ways to the progress of the science and especially 

 to our knowledge of th ■ flora of the principal Dutch islands, but 

 without leaving any sitisfictory general view of all that was 

 known on that of the whole archipela'^o. lilume's " Bij Iragen 

 tot de Flora van Nedeilandsch Indie," drawn and published at 

 Eatavia when he was .still very young, ivas a wonderful work con- 

 sideiing the means at his disposal ; and ofierhis return to F^urope 

 he commenced elucidating with equal ability and in greater de- 

 tail several orders connected with that flora ("Flora Java;," "Rum- 

 phta," "Musium LugdunoBatavense"); Ijut as general works all 

 these remained incomplete. Miquel drew up a " Flora I nd ice 

 Batavia;," purposing to be complete as far as his materials 

 allowed ; but it was far too hastily compiled, without the necessary 

 critical examination of genera and species. Since his lamented 

 death I have seen no signs of any Dutch successor likely to take 

 up the study of the botany of the archipelago in any scientific 

 point of view. In the meantime the rich stores collected by P. 

 Beccari in Saraw.ak are, I am informed, in the course of distri- 

 bution ; and that enterprising Italian naturalist has returned to 

 the East with a view to the exploration of New Guinea and some 

 otiiers of the less known islands. 



Grisebach, in his Indian Monsoon region, unites the archi- 

 pelago with the East Indian peninsulas and continent to the foot 

 of the Himalayas, the Island of Ceylon to the west, and the 

 Society and the Marquesas and other coral islands to the east, 

 emliracing, as it were, the whole of Tropical Asia or Sclater's 

 Indian, with a portion of his Ausiralian Pakeotropical regions; 

 and certainly a cursory survey of the vegetation of thii vast ex- 

 panse of territory would appear to justify Grisebach's idea of its 

 unity of character. It his also tolerably definite limits deter- 

 mined on the north-west by tlie drier rocky East Mediterranean 

 or Persian region, on the north by the great Himalayan chain, 

 and on the east and south by a wide extent of ocean ; the ex- 

 cepiions being chiefly the above-mentioned innooulation, as it 

 were, into the Japanese flora to the north-east, and more or less 

 of an intrusion across the ocean to the westward into Tropical 

 Africa, and over a narrower interval of sea to the south-east into 

 north-east Australia. The principal cause of this uniformity of 

 character, so far as it g les, is well deduced by Grisebach from 

 climatolo.^ical and physical conditions, his observations on the 

 chief portion of the region, or East India proper, from Ceylon and 

 the Peninsula to Malacca, being mainly derived from Hooker and 

 Thomson's most instructive introduction to their" Flora Indica," 

 wdiich, from a variety of causes, was unfortunately ])ut a stop to 

 after the issue of the first volume. It is now being replaced 

 by the " Flora of British India," under Dr. Hooker's editor- 

 ship, of which the first part, just published in a more concise 

 form, gives a confident hope that it may be steadily and rapidly 

 brought to a conclusion. We shall then have ample means of 

 instituting a comparison of the Indian vegetation with that of 

 Boissier's " Flora Orientalis " to the north-west, of Ledebour's 

 "Flora Rossica " to the north, of Miquel's almost as complete, 

 though less methodical enumerations of Japanese plants to the 

 north-east, of the " F'lora Australiensis" to the south, and of 

 Oliver's " Tropical African Flora " to the west. 



The " Flora Indica " does not, however, extend fo the eastern 

 portion of Grisebach's Monsoon region, about which our in- 

 formation is so deficient ; but where, as he observes, " the dis- 

 tribution of organisms involves one of the most remarkable 

 problems in the darker regions of vegetation-centres." He 

 further remarks that llie flora of this eastern region, with the 

 exception of the Timor group, is everywhere Indian, and regu- 

 lated by climatological conditions, the vegetation of New Guinea 

 being, as he rather hastily supposes, "thoroughly similar to that 

 of Borneo," a result quite at variance with the distribution of 

 animals as expounded by Wallace. As a possible explanation of 

 this discrepancy, he proposes an hypothesis which, for fear of 

 misrepresentation, I shall give at length: — "Thus the limits of 

 particular forms of plants and of animals in the Indian Archi- 

 pelago do not concur. Vegetation corresponds to climatological, 

 the fauna to local (riiiintluhc) analogic*. This opens a wide field 

 for speculation on the history of the globe. By a mere sinking 

 of the land to an unimportant extent, Darwinism readily explains 

 the origin of the fauna of these islands, but not the Indian 

 c'laracter of the flora of New G'line.i, which presupposes much 

 greater upheavals than the origin of fauna, calcuLiled to give 

 rise to equatoiial rainy seasons. This hypothesis would daive 

 the endemic marsupials of New Guinea fiom the .A.ustra'.iin ones 

 after the establishment of the Torres Straits, but it gives no ex- 



