188 BERRY— LOWER EOCENE FLORA OF [April 25, 



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

 midotorce and Planirotse, the latter with two tribes Galphimiese and 

 Malphighieae are entirely American. Of the three tribes into which 

 the Pyramidotorae is divided the Tricomariese are entirely American, 

 the Hiraeeae 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 Banisteriese, 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- 

 stcira confined to Madagascar : Flabcllaria confined to Africa: Can- 

 canthus confined to Arabia: Brachylophon confined to farther India: 

 Mezia, Diploptcvis, Lophopteris, Clonodia, Colcostachys, Blcpliaraii- 

 dra, Loplianthera, J'cmtcalaria, Ptcrandro, Acmanthera, Diacidia, 

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

 phytutn confined to Cuba: Lasiocarpus and Echinoptcris 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 a> 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. Xo forms are known 

 from the L'pper Cretaceous for although Ettingshausen recorded a 

 species of Malpighiastrutn and one of Banisteriophyttum from the 

 Upper Cretaceous of Australia, those identifications are open to the 

 most serious question 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 Malpighiastrutn, Hiraa and Banis- 

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

 Ilircca and Banisteria in the Wilcox flora, based upon both leaves and 

 characteristic fruits. There are also doubtful species of Malpighias- 



