Origin of the Angiospermous Flora of South Africa. 345 



two orders originated in the Southern Hemisphere from common 

 ancestors (compare Drude in Engler-Prantl, iv., 1, 1897, p. 29). 

 As regards the Eutace^ Bngler has pointed out (Engler-Prantl, iii., 

 4, p. 106) that the Xanthoxylcce must come nearest the original type 

 of the order. From these he supposes the Cuspariece, Boroniece, and 

 DiosmecB to have developed. The first are very richly developed in 

 South America, the second in Australia, the third in South Africa, 

 especially in South- West Cape Colony, but whether this points 

 to a common origin in the Southern Hemisphere does not seem to 

 be at all clear. 



The PenceacecB and allied orders (the ThymelcBales) also fail to give 

 "US in their distribution an indication of their origin. 



Pen^eace^ nearly allied to Thymelaeaceae ; only distinguished by 

 4-merous ovary with 2-4 ovules each. All in South-West Cape 

 Colony ; 21 species and 5 genera. 



Geissolomace^. 1 monotypic genus ; closely allied to Penaeaceae, 

 with which the order has frequently been united. South -West 

 Cape Colony. 



Oliniace^. Fruit a drupe, while in the two previous orders the 

 fruit is a capsule. About 6 species : 4 in Cape Colony, 1 in Usambara, 

 1 in Abyssinia. 



Thymel^eace^, with the exception of the polar regions distributed 

 over the whole globe, but many genera and groups very 

 localised. 



Peddiea. 6 species, South-Bast and Tropical Africa. 



Gnidia. 80-90 species, Tropical and South Africa, Madagascar, 

 and East Indies. 



Struthiola. 24 species, mostly in South Africa, 3 in Tropical 

 Africa. 



Cryptadenia. 4-5 species. Cape. 



Lachncea. 18 species, Cape. 



Passerina, 4 species, and Chrymococca, 1 species. Cape ; 2 allied 

 genera in Central and Northern Asia. 



Dais. 2 species : 1 in Natal and 1 in Madagascar. 



ELiEAGNACEiE. Chiefly in the northern temperate and sub- tropical 

 ^one ; none in the Southern Hemisphere. 



The Bruniace^, 12 genera and over 40 species, which are re- 

 stricted to South Africa, and even almost entirely to South-West 

 Cape Colony, are so isolated amongst Saxifraginse that we can also 

 only point to their antiquity. About their origin no guess can be 

 hazarded. 



There are a number of genera of large orders which must be 

 placed in the same category, e.g., Gliffortia (about 40 species, mostly 



23 



