150 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



times obliquely, inequilateral base. Margins entire. Texture coria- 

 ceous. Length ranging from 10 to 13 mm. Maximum width, mid- 

 way between the apex and the base, 4 to 5 mm. IVIidrib stout, promi- 

 nent below, channeled above, relatively straight. Secondaries 

 prominent, numerous, subparallel, camptodrome. 



This species is well marked and readily distinguished from the 

 other members of the Potosi flora. It is comparable with the exist- 

 ing Drepanocarpus lunatus Meyer, a widespread form ranging from 

 the West Indies and southern Mexico to Brazil, and recorded also 

 from tropical West Africa. Drepanocarpus is not otherwise known 

 in the fossil state. The existing species comprise 8 to 10 trees or 

 high climbing shrubs, all of which are confined to tropical America 

 with the single exception noted above. 



Genus AESCHYNOMENE Linnaeus. 



AESCHYNOMENE BOLIVIANUM (Engelhardt). 



Plate 17, fig. 12. 



Hedysarum bolivianum Engelhardt, Sitz. Natunv. Gesell. Isis in Dresden, 1894, 

 Abh. 1, p. 7, pi. 1, figs. 62, 63. 



Description. — Leaflets small, sessile, obovate in outUne, with a 

 broadly rounded tip and an acuminate base. Margins entire. Tex- 

 ture membranaceous or chartaceous. Leaf substance thin. Length, 

 about 7 ram. Maximum width, in the middle part of the leaflet, 

 about 3.5 mm. Midrib thin, curved. Secondaries thin, numerous, 

 equally spaced, subparallel, camptodrome. 



This species was described by Engelhardt, who compared it with 

 the existing and polymorphous AescJiynomene falcatum De Candolle, 

 which ranges from Mexico to Brazil. It has not been recognized in 

 the other collections from Potosi. I have transferred this form to 

 the genus AescJiynomene with the recent species of which Engel- 

 hardt compared it and which it resembles more closely than it does 

 Hedysarum. The latter is a genus with over three score existing 

 species of herbs or shrubs of the temperate regions of Europe, Asia, 

 Africa, and North America. The genus AescJiynomene, on the other 

 hand, is confined to the tropics of both hemispheres, with numerous 

 existing species of herbs or shrubs, well represented in the Brazihan 

 region. 



Genus SWEETIA Sprengel. 



SWEETIA TERTIARIA Engelhardt. 



Plate 17, fig. 13. 



Sweetia tertiaria Engelhardt, Sitz. Naturw. Gesell. Isis in Dresden, 1887, Abh. 5, 

 p. 38, pi. 1, fig. 11; 1894, Abb. 1, p. 9, pi. 1, fig. 26.— Britton, Trans. Amer. 

 Inst. Min. Eng., vol. 21, 1893, p. 254, fig. 79. 



Description. — Leaflets sessile, nearly equilateral, ovate in general 

 outline, with a rounded or emarginate apex and a cuneate base. 



