19I4-] SOUTHEASTERN NORTH AMERICA. 193 



those in which the carpels are reduced in number, and in the more 

 evolved families the flowers have become zygomorphic. Since there 

 are several distinct lines of development and the separation from the 

 Geraniales is based on characters that seem trivial, it seems probable 

 that the families comprising these two orders as at present under- 

 stood represent a plexus of forms whose filiations are not yet 

 understood. 



The first family of the Sapindales that is represented in the 

 Wilcox flora is the Anacardiacese, an exceedingly natural group. It 

 contains about 58 existing genera and 435 species of shrubs and trees 

 with round pithy branches, resinous and frequently toxic juice, 

 alternate, simple, palmate or pinnate, exstipulate leaves, and dru- 

 paceous fruits with exalbuminous seeds. The Anacardiacese makes 

 its greatest display in the tropics and subtropics of both hemispheres 

 but in the existing flora is especially characteristic of the Malaysian 

 region. Rhus is by far the largest genus and the only one of the 

 family found in the extra tropical regions of both the northern and 

 southern hemispheres. The present geographical distribution shows 

 many anomalies throughout the family. Thus the genus Campo- 

 sperma Thwaites has eight species in Madagascar, Ceylon, Sumatra, 

 Borneo and the Malaccas and a single species in northern Brazil. 

 The genus Sorindeia Thouars of tropical Africa and Madagascar is 

 most closely allied to the genus Alauria Kunth of the Andes of South 

 America. The genus Calcsium Adanson has 13 species in tropical 

 Africa and one in the East Indies. The Eurasian genus Pistacia 

 Linne has a single species in Mexico. The genus Thyrsodium Ben- 

 tham has 4 species in the Amazon region of South America and one in 

 tropical West Africa. The subfamily Mangiferae with about 80 

 species is entirely Malaysian except for a species of Glutei Linne in 

 Madagascar and the genus Anacardium Linne which is confined to 

 tropical South America, chiefly in Brazil. The subfamily Spondiea? 

 is found in the tropics of all the continents, excepting Europe. The 

 subfamily Rhoidea? is found on all the continents and shows a pairing 

 of a considerable number of genera in equatorial Africa and America. 

 The two remaining subfamilies, the Semecarpere and the Dobineea? 

 are restricted to the region extending from India to Australia. The 



PROC. AMER. PHIL. SOC, LIII, 214, M, PRINTED JULY 13, I914. 



