106 



one as shown by its occurrence in post-glacial deposits at very- 

 many localities beyond its present range in Russia, Finland, 

 Sweden and Denmark. The two other existing species are 

 Trapa bicornis L., and Trapa bispinosa Roxb., of southeastern 

 and southern Asia and said also to occur in Africa. 



The genus has an extended geological history. Rosettes sup- 

 posed to represent the floating leaves {Trapa ? microphylla Lesq., 

 and Trapa ? cuneata Knowlt.) are widespread in the Rocky 

 Mountain province in beds of late Cretaceous and early Tertiary 

 age. The oldest recognizable fruits are a large bi-cornute form 

 from the Eocene of Canada and Alaska and Trapa wilcoxensis de- 

 scribed in the following paragraph. An Oligocene species {Trapa 

 Credneri Schenk) has been described from Saxony, and no less 

 than seven species have been described from the Miocene — two 

 occurring in Idaho (Payette formation), one in Japan and the 

 balance in Europe, where two species continue into the Pliocene. 

 A species from the late Pliocene of America is also described in 

 the present note. The existing Trapa natans has been recorded 

 from the preglacial beds of England and Saxony and from very 

 many interglacial and postglacial deposits in Portugal, Italy, 

 Netherlands, Germany, Sweden, Russia and Denmark, Gunnar 

 Andersson in a recent paper (1910) mentioning 18 localities in 

 West Prussia, 6 in Denmark, 17 in Sweden and 29 in Finland. 

 With this short prefatory statement the two following species 

 may be briefly characterized. 



Trapa wilcoxensis sp. nov. 



Fruit relatively small, rhomboidal in outline, wider than high, 

 indehiscent, coriaceous, armed with two more or less extended, 

 laterally directed or ascending (not recurved) horns. Width 

 1.3 cm. to 1.8 cm. Height 7 mm. to 9 mm. Somewhat com- 

 pressed (naturally), expanded medianly, broad and extended 

 below, more or less extended and rounded above. Horns stout, 

 conical, more or less extended. Surface more or less tuberculate 

 medianly. Figs. 1-3. 



This species comes from the middle Wilcox of the Lower 

 Eocene at Peryear, Henry County, Tennessee. It shows con- 

 siderable variation in size and relative development of horns and 



