MR. G. BEOTHAM OK EUPHOHBIACE.E. 255 



From the above data we may conjecture that Phyllanthus in 

 its general sense had its most ancient centre in the African or 

 Mascarene region, spreading very early eastward over the Indo- 

 Australian region and westward into tropical America, in both of 

 which it has since prospered and divided more than in Africa 

 itself, and more in the Indo-Australian than in the Arneri 



ican 



region. 



The distribution of the two great amphigeous petaliferous 

 genera is somewhat different. They are eminently American, the 

 evidence of African origin much slighter, though perhaps still 

 traceable. Jatropha especially, with 68 species, has only about 

 1<> in the Old AVbrld, of which about a dozen are African and 2 

 Asiatic, besides the ubiquitous J Cicrcas. The African ones 

 belong chiefly to the section Adenoropium, with free petals ; but in 

 that section they present a few distinct forms extending south- 

 wards beyond the tropics to the Cape itself; there are also two 

 or three of the east tropical African species that acquire the 

 adaptive character of succulent, sometimes aculeate branches, and 

 reduced leaves, peculiar to succulent regions. The typical Curcas 

 is now widely spread over the tropical regions of the New and 

 the Old World, chiefly near the sea ; and Indian botanists have 

 no doubt of its being really wild at least in the Peninsula. Seve- 

 ral American stations are given by collectors with doubts of its 

 being indigenous ; but in most cases it is sent as really American. 

 Lhe only other species, however, of the same subsection, J. Wight- 

 tana, Muell. Arg., is from the Indian peninsula. The other sub- 

 sections of Curcas, Loureira and Mocinna, are American, and 

 present some very distinct species of limited areas from the 

 Alexicano- Cuban region, some of them of a succulent or aculeate 

 character ; and to these the Cuban aculeate Acidocroton is so 

 nearly allied that it might almost be considered a congener. 

 I he American species of the section Adenoropium and the species 

 of the exclusively American and very distinct section Cnidoscolus 

 are mostly wide-spread and variable. With regard to the con- 

 nexions of the aggregate genus, there are none very close ; and of 

 niore divergent allied genera there are but few. None are known 

 m Africa. In eastern South America Hevea and its allies may 

 be in some measure connected, and Manihot may possibly be a 

 derivative, though all connexion is now completely severed. West- 

 w ard Aleurites may be one of the nearest relatives to Jatropha ; 

 J ts two well-known species are natives of the South-Pacific islands 



u2 



