NA TURE 



441 



THURSDAY, JUNE i, 1911. 



T' 



AFRICAN VEGETATION. 

 Die Vegetation der Erde. Sammliing pflauzen- 

 gcographischer Moiwgraphien. By Prof. A. 

 Engler and Prof. O. Drude. ix., Die Pflanzen- 

 welt Afrikas, insbesondere seiner tropischen 

 Gebiete. Grundziigc der Pflanzenverbreitung' in 

 Afrika und die Charakterpflanzen Afrikas. By A. 

 Engler. Band i., .Mlgemeiner Uberblick iiber die 

 Pflanzenwelt Afrikas und ihre Existenzbedingungen. 

 I Halfte (Heft i.), pp. xxviii + 478. 2 Halfte (Heft 

 ii., und iii.), pp. xii + 479-1029. (Leipzig: VV. 

 Engelmann, 1910.) 



HE botany of Africa, especially of tropical .Africa, 

 has for the last twenty years attracted much 

 ■tfention among systematists, both in this country 

 ;;(! on ihr Continent of Europe. The important and 

 vhaustive "Floras'* of South and Tropical Africa 

 rJ,^'u^ised at Kew have, after a period of abeyance, 

 proi^-ressed steadily towards completion. Many books 

 and papers dealing with more restricted areas have 

 been published, such as the enumeration of Dr. Wel- 

 witsch's Angolan collections, the important work on 

 rlie vegetation of German East Africa, edited bv Dr. 

 Kngler, of Berlin, and Dr. Wildemann's finely illus- 

 trated volumes on the botany of the Congo region, 

 i'he results of various expeditions, many of which 

 have been largely due to individual effort, have also 

 ■ idded much to the botanical literature of this great 

 (ontinent. Towards the achieving of these results no 

 one has worked harder or displayed greater zest than 

 Dr. Engler. Not only has he made good use of the 

 members of his staff at the Berlin Botanical Museum 

 in working up the great mass of material which has 

 l)«on collected chiefly from the German colonies, but 

 has also himself made botanical expeditions in various 

 I parts (if the continent. Dr. Engler was therefore 

 eminently fitted to prepare a general account of the 

 vegetation of .Africa, and the two substantial volumes 

 in which this account is embodied form a valuable 

 addition to the important series of monographs on 

 l)lant geography issued under his own and Prof. 

 Oscar Drude's editorship. 



The greater part of the book, to be precise 870 out 

 of a total nf 10 19 pages, is occupied with the intro- 

 fiurtioii, a general review of the vegetation of the 

 continent. This takes the form of a series of chapters 

 descriptive of the vegetation of as manv areas differ- 

 ing largely in size and importance. Chapter i. 

 (pp. 1-50) deals with Mediterranean Africa, from 

 Morocco to Egypt, and the .Sahara. Chapter ii. 

 (nt). 51-478), "Tropical East .Africa to Eastern Cape- 

 land," deals with the vast area extendingr from Nubia 

 and .Somaliland to the Karroo district of Cape Colony, 

 and includes among its principal subdivisions the 

 Abyssinian flora, the floras of the Somali peninsula, 

 if the Masai highlands, of German East Africa, 

 Nyasaland, Portuguese East .Africa, Rhodesia, the 

 last Kalahari district, and the Karroo. The rich and 

 characteristic flora of south-west Cape Colony forms 

 the subject of the third chapter, while the fourth- 

 NO. 2170, VOL. 86] 



"the extra-tropical and tropical summer-rain district 

 of West Africa " — is concerned with the enormous 

 area stretchinR- from Namaqualand and Hereroland 

 to Senegambia, and including the Huilla highlands, 

 Angola, the Congo basin, the area of central tropical 

 .Africa from the Upper Congo to I'ganda and the 

 Great Lakes, the Ruwenzori district, the Cameroons 

 (treated in some detail), Central Guinea or Togo- 

 land, Upper Guinea, and Senegambia. The fifth and 

 last chapter deals with the vegetation of the Cape 

 Verdes, the Canary Islands, and Madeira. 



.A perfect uniformity of treatment of these numerous 

 and widely different areas, some only of which have 

 been indicated above, could not be expected, and Dr. 

 Engler is naturally most exhaustive in dealing with 

 provinces the botany of which he has had most oppor- 

 tunity of knowing, namely, those under German 

 government in East and West .Africa. But his review 

 as a whole forms a valuable rdsumi of the work 

 which has been done on the botanv of the various 

 parts of the .African continent, and gives, so far as 

 is possible from the data to hand, a usefukaccount 

 of the chief characteristics of their vegetation. It 

 shows not only what has been done, but, a matter of 

 equal importance, what still remains to be done. 

 Perhaps the most striking feature of this portion of 

 the work is the wealth of illustration ; the pictures 

 occupy almost if not quite as much space as the text. 

 There are more than fifty whole-page pl.itos, beau- 

 tiful photographic reproductions of vegetal ion, ]ilant 

 associations, or landscape. In addition there are 

 more than 700 text figures, many of which occupy 

 a full page; these illustrate habit or form of indi- 

 vidual plants, or are botanical analyses of one or 

 more species. The illustrations alone give a good 

 idea of the characters of the vegetation of the district 

 under discussion. Mention should also be made of 

 the carefully elaborated list of botanical rolloctors 

 classified according to districts, which i)rece(les the 

 text proper. .Associated with this is a map indicating 

 the routes and collecting stations of the more impor- 

 tant collectors. Three other maps illustrate the vege- 

 tation of German South-West .Africa, the Cameroons, 

 and Togoland respectively. 



The comparatively small portion of the book which 

 remains after the introduction, is divided into four 

 parts. Part i. deals mainly with climate tempera- 

 ture and rainfall — of the tropical and north and ^outh 

 extra-tropical areas; it also includes a chapter on the 

 nature of the soil. Part ii. gives a brief general 

 account of the veg(>tation of a series of altitudinal 

 regions— tropical rain forest, tropical steppe region, 

 subtropical bush and grass region, subtropical h'gh 

 forest region, and subalpine and alpine regions. 

 Part iii. deals similarly with the various formations 



halophilous, including littoral and interior (<vch as 

 occur in the Sahara in the north, and the Kalaliari in 

 the south); hydrophilous, including alluvial forest, 

 marshland, lake, and river vegetation ; hygrophilous 

 megatherm, the evergreen rain-forest vegetation; 

 hygrophilous mesotherm — the bamboo forest, high 

 mountain bush, and damp meadow veg<'tation of the 

 higher regions of the tropical mountains or the slopes 



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