NATURE 



56? 



THURSDAY, OCTOBER 11, 1900. 



A NEW GEOGRAPHY OF PLANTS. 

 Pflanzen- und Tierverbreitiing. Von Alfred Kirchhoff. 

 Hann, Hochstetter, Pokorny, Allgemeine Erdkunde. 

 Fiinfte Auflage, von J. Hann, Ed. Bruckner und A. 

 Kirchhoff. iii. Abteil. Mit 157 Abbild. im Texte, u. 3 

 Karten in Farbendruck. Pp. 327. (Prag u. Wien : 

 F. Tempsky. Leipzig: G. Freytag, 1899.) 



TO see a portion of my special domain surveyed by 

 an authority in another branch of science appeals 

 to me in a particularly interesting and instructive light, 

 especially if it comes from a man of judgment and broad 

 views. Such a survey may expose any bias, and is likely 

 to open up new vistas. Dr. Kirchhoff, professor in the 

 University of Halle, is a geographer of repute, and 

 naturally approaches the facts of distribution of plants 

 and animals from a point of view dift'erent to that of a 

 botanist or zoologist. It is true his book is intended as 

 an introduction to phytogeography and zoogeography for 

 the student of physical geography, and not as a critical 

 essay on these branches ; yet its merits seem to demand 

 that we should rank it higher and. judge it accordingly. 

 It is not a mere abstract of one of the few well-known 

 treatises on the distribution of plants and animals, made 

 to serve as a text-book for the beginner, but the product 

 of a mind evincing a considerable power of assimilation 

 of matter, necessarily foreign to it in many of its details, 

 and with an admirable grasp of that which is essential. 

 With these accomplishments are combined the gift of a 

 lucid exposition and of a language which is, apart from 

 certain idiosyncrasies of expression, clear and pleasant. 



The author reminds the reader in the preface that in I 

 the earlier editions of Hann, Hochstetter and Pokorny's 

 "Allgemeine Erdkunde," the corresponding part was 

 written by Dr. A. Pokorny ; that the progress of phyto- 

 and zoo-geography has rendered it necessary to recast the , 

 whole ; and that it is written more especially for the ; 

 students of geography, and excursions into the domain 

 of the naturalist had therefore to be avoided. Yet i 

 geography on the one side, and botany and zoology on 

 the other, overlap to such an extent within the compass ! 

 of phyto- and zoo-geography, that the author was naturally 

 obliged to fall back over and over again on the botanist 

 or zoologist, who supplied him, if I may say so, with the 

 woof to his warp. It is here where, as one might 

 expect, the weak points of the book become evident ; and 

 it is a pity that the author did not avail himself of the 

 aid of a competent botanist for final revision. I suppose 

 the same applies to the zoological details. Reckless j 

 statements, as, for instance, that a single individual of 

 Sisyinbriu7n sophia produces 720,000 seeds, or that most 

 of the 854 species of the Egyptian flora are introduced, 

 or that Southern Italy (exclusive of Sicily) possesses 

 3132 species against 9000 for the whole of British India^ 

 i.\;c., can hardly be excused by the desire of putting the 

 case as emphatically as possible. Instances of a decided 

 looseness of expression in describing certain facts 

 would have been discovered at once by a botanical critic, 

 e.g. when the author says, on p. 18, that the plants derive 

 NO. 1615. VOL. 62] 



their " principal food " from the soil, while he applies the 

 same term, on p. 24, to the carbon dioxide of the atmo- 

 sphere ; when he quotes the orchids and aroids of the 

 equatorial zone as examples of parasites (p. 19), although 

 he describes them quite correctly as epiphytes in another 

 place ; and again, when he attributes " genuine grass 

 leaves" to the Australian Xanihorrhoea (p. 112). Slips, 

 also, like that on p. 162, where the " Rose of Jericho" is 

 figured as Asteriscus pygmaeus., a member of the order 

 of Compositoe, but described in the text as a " little 

 Cruciferous plant {Anasiatica hierochuntica)^'' or on 

 p. 198, where the author speaks of the " Kompositen- 

 geschlecht der . . . Caesalpinien," call for the helping 

 hand of the botanist. Willows are not wind-fertilised 

 (p. 51) ; Rhododendron ponticum is by no means killed by 

 - 2^^ C. (p. 86) ; the peach has not originated in Southern 

 Asia (p. 135) ; there is no transformation of our ordinary 

 grape-vine into an evergreen plant in the tropics ; these 

 are statements which should be repeated no longer in 

 text-books. It would be easy to quote a good many more 

 mistakes of this order, but I do not wish to dwell on them 

 more than is necessary to show where, in a future edition^ 

 careful revision must be undertaken. 



The book is divided into three parts. The first part 

 occupies 139 pages, and deals with general telluric con- 

 ditions in relation to the organised world, the second 

 (88 pages) with the phytogeographical divisions (Flora- 

 reiche), the third (100 pages) with the zoogeographical 

 divisions (Faunareiche). The first part is subdivided 

 into five sections, dealing with (i) the reproductive and 

 migratory capacities of the organisms, (2) the natural 

 conditions of vegetable and animal life, (3) the variability 

 of organisms, (4) the Theory of Descent and its geo- 

 graphical proofs, and (5) the general principles of the 

 distribution of plants and animals. To condense this 

 abundance of matter into 139 pages is a very difficult 

 task, and that it has been done on the whole so satis- 

 factorily says much for the judgment of the author. 



In the following two p9.rts. Prof. Kirchhoff has set 

 himself the task of characterising the principal geo- 

 graphical divisions of the organic world, relying, of 

 course, on the researches of the recognised authorities in 

 phyto- and zoo-geography, but viewing them from the 

 more comprehensive standpoint of the geographer, as it 

 appeared to him " desirable for a more vivid compre- 

 hension of the nature of the countries of the globe." 

 The separation of the vegetable and the animal kingdom 

 into floras and faunas, their distribution in the present, 

 their harmony with the physical character of their re- 

 spective areas, and their mutual adaptation within each 

 area, are the result of a process of evolution in which the 

 shaping, selecting, separating and shifting forces have 

 been, for both kingdoms, the same to such an extent 

 that a far-reaching parallelism in their geographical 

 differentiation is to be expected a priori. This has been, 

 perhaps, too often lost sight of by specialists. 



On the other hand, the modern geographer, from the 

 very fact that he starts with conditions bringing about 

 that parallelism, would be naturally led to a more uniform 

 conception of the differentiation of the organic world into 

 floras and faunas. The result of this has been, in Prof. 

 Kirchhoff's case, the almost complete congruence of the 



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