E. V. Wulfif 



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Historical Plant Geography 



and absent in Asia, or more widely distributed on them than in tropical 

 Asia. As examples of type of area we may cite the following: 



The genus Symphonia of the family GuUiferae is represented by the 

 species 5. globulifera, a small tree growing in western Africa from 

 Gabon to Angola, and then is distributed in the forests of Brazil and 

 also in the Guianas, Panama, Costa Rica, Honduras, and the West 

 Indies. This species is not found in eastern Africa, but in Madagascar 

 there grow five other closely related species. 



As a second example we may take the family Vochysiaceae, which is 

 purely American except for the genus Erismadelpkus, recently found in 

 the forests of the Cameroons. 



The genus Anona, most of whose species are distributed in America 

 but which is likewise cultivated in Africa, is also represented on the 

 latter continent by wild species, such as A . glauca in upper Guinea, A . 



Fig. 15. — Pantropic discontinuous area of the genus Buddleia (Loganiaceae). (After 

 Hutchinson). 



Klainii in Gabon, and A. senegalensis, closely related to the American 

 species, a wild form found in all the steppe regions of Africa. 



e. India-Malay Type.— This type embraces the discontinuous areas 

 of species distributed in India, Malaysia, Polynesia, and also in some 

 cases in tropical Australia, particularly the northeastern part. As ex- 

 amples of this type we may cite the genera Agathis, Araucaria, Dacry- 

 dium, Areca, Engelhardtia, Cochlospermum, Hernandia, and Cratoxylon. 



Here we may refer also the discontinuous areas of plants found in 

 Malaysia, Polynesia, AustraHa, and New Zealand. According to 

 Oliver, in the flora of the last-mentioned country we find a consider- 

 able number of elements that are common to both New Zealand and 

 Malaysia. For instance, the genus Dacrydium, represented by several 

 species in Malaysia and New Caledonia, has 7 species in New Zealand 

 and I in Tasmania; it also has i species in Chile, D. Fonckii, close to 

 the New Zealand species, D. laxifolium. 



9. Gondwana Type. — In this group we include, in conformity with 

 paleogeographical data, those discontinuous areas embracing India, 



