188 BERRY— LOWER EOCENE FLORA OF [April 25,, 



Of the two subfamilies into which the family is divided — the Pyra- 

 midotorae and Planirotse, the latter with two tribes Galphimieee and 

 Malphighiese are entirely American. Of the three tribes into which 

 the Pyramidotorse is divided the Tricomariese are entirely American, 

 the Hirseese have 3 genera and 23 species confined to Asia, 3 genera 

 and 12 species confined to Africa, a genus with 12 species ranging 

 from Malayasia to Australia, and 9 genera with 151 species confined 

 to America. The remaining tribe, the Banisterieae, has a monotypic 

 genus in Asia, 2 genera and 15 species in Africa, a single genus with 

 7 species ranging from the East Indies to Australia and 11 genera 

 with 247 species confined to America. 



There are 21 monotypic genera distributed as follows: Micro- 

 steira confined to Madagascar : Flahellaria confined to Africa : Cau- 

 cawf/jw5 confined to Arabia : Brachyloplion confined to farther India: 

 Mesia, Diplopteris, Lophopteris, Clonodia, Coleostachys, Blepharan- 

 dra, Lophanthera^ Verrucalaria, Pterandra, Acmanthera, Diacidia, 

 and Glandonia confined to Brazil, Guiana and Venezuela: Henleo- 

 phytnm confined to Cuba: Lasiocarpiis and Echinopteris confined to 

 Mexico: and Tricomaria and Mionandra confined to Argentina. 



Monotypic genera in general are susceptible of two interpreta- 

 tions, i. e., they represent either the last survivors of a long line as in 

 the case of the Ginkgo, Sassafras, etc., or they represent relatively 

 recent specializations. In the case of the foregoing monotypic 

 genera it seems probable that the majority are the result of relatively 

 recent evolution since there is nothing in their character or distribu- 

 tion to suggest any extended geologic history and none have been 

 found in fossil floras. 



The fossil record is most incomplete. No forms are known 

 from the Upper Cretaceous for although Ettingshausen recorded a 

 species of Malpighiastriim and one of Banisteriophyllum from the 

 Upper Cretaceous of Australia, those identifications are open to the 

 most serious cjuestion and I do not consider them of any weight in a 

 discussion of this kind. The family is certainly represented in the 

 lower Eocene by five species of Malpighiastrum, Hircca and Banis- 

 teria in the Ypresian of the south of England and by five species of 

 Hircra and Banistcria in the Wilcox flora, based upon both leaves and 

 characteristic fruits. There are also doubtful species of Malpigliias- 



