634 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



from Florissant. It may also be compared with various identifica- 

 tions of RhaniMus rossmdssteri Unger, as, for example, the leaves 

 figured by Heer ^ from the Miocene of Switzerland. The latter 

 species is rather common in Europe from the Aquitanian to the 

 Pliocene and shows considerable variation. It is, in general, a some- 

 what larger form than the present species. 



Rhamnus is a rather common element in Miocene floras both in 

 this country and abroad. Its known history extends from the 

 Upper Cretaceous to the present, and it is especially abundant in 

 the early Tertiary of the western United States. The existing species 

 number about three score shrubs and small trees widely distributed 

 in all temperate and many tropical parts of the world except Aus- 

 tralia and the Pacific islands. There are eight species and three 

 varieties in the existing flora of the United States of which the 

 eastern Rhamnus caroliniana Walter, a stream bank and bottom- 

 land species, extends westward to eastern Nebraska, Kansas, Okla- 

 homa, and Texas. I do not know of its occurrence in the "pan- 

 handle " region, however. 



The humid demanding mesophytic species of the Cretaceous and 

 Eocene appear to have given rise to two physiologically divergent 

 lines — one dwellers in bottoms, along streams and as undershrubs 

 in forests — the other becoming inured to scanty water conditions, 

 bright sunlight, high evaporation, etc., and giving rise to the chapar- 

 ral and montane species of the Eocky Mountains and Pacific coast 

 region. 



Lesquereux's material of Rhamnus lesquereuxi from Florissant is 

 said to be in the collections of Princeton University. The Okla- 

 homa material is in the United States National Museum. 



Eolotype.—Q^t. No. 35288, U.S.N.M. 



Order EBENALES. 



Family SAPOTACEAE. 



Genus BUMELIA Swartz. 



BUMELIA OKLAHOMENSIS, new species. 



Plate 94, fig. 1. 



Leaves oblong-obovate in outline, with a rounded tip and a nar- 

 rowly cuneate base. Length about 5 cm. Maximum width, at or 

 slightly above the middle, 1.75 cm. Margins entire. Texture sub- 

 coriaceous. Extreme base and petiole missing in the present mate- 

 rial. Midrib very stout and prominent, somewhat curved proximad. 

 Secondaries extremely thin, numerous, subparallel; they diverge 



*Heer, O., Fl. Tert. Helv., vol. 3, 1859, pi. 124, figs. 18-20. 



