NO. 2229. FOSSIL PLANTS FROM BOLIVIA— BERRY. 159 



This species was described by Engelhardt and has not been recog- 

 nized in the collections from Potosi studied by me. It was compared 

 with the existing Gaylussacia ledifolia Martins, a Brazilian species. 

 Gaylussacia has many existing species of shrubs and undershrubs 

 widely distributed in the Western Hemisphere from the equator well 

 into both the North and the South Temperate Zones. The maximum 

 of species occur in Brazil. On the other hand, the allied genera 

 Gaultheria and Vaccinium have numerous Andean species from Cen- 

 tral America to Chile, and the fossil species may possibly be more 

 closely related to some of the existing species in the last two genera 



Order GENTIANALES. 



Family APOCYNACEAE. 



Genus APOCYNOPHYLLUM Unger. 



APOCYNOPHYLLUM POTOSUNUM, new species. 



Plate 18, fig. 13. 



Undetermined leaf, Bkitton, Trans. Amer. Inst. Min. Eng., vol. 21, 1893, p. 2-59, 

 figs. 64,. 67. 



Description. — Leaves narrowly linear lanceolate, more or less fal- 

 cate, with a gradually narrowed acuminate apex and base, presuma- 

 ably sessile. Margins entire. Texture coriaceous. Midrib stout 

 and prominent, curved, expanded proximad. Secondaries remote, 

 diverging from the midrib at wide angles, straight to near the mar- 

 gin where their ends are joined by flat arches. Thin percurrent veins 

 subparallel with the arches usually present half way between them 

 and the midrib. Lengtli ranging from 5 to 6 cm. Maximum width, 

 in the middle part of the leaf, ranging from 3 to 6 mm. 



Leaves of tliis character have been referred to the genus C'allis- 

 temon of the Myrtaceae and to the genus Grevillea of the Proteaceae 

 as well as to the form genera Acerates and Apocyno'pliyUum. The 

 last, established for fossil forms of the Apocynaceae of uncertain 

 generic identity, seems to be the proper reference for these Potosi 

 forms which are not uncommon although usually broken. The form 

 and venation are very characteristic. Lack of sufficient recent 

 material renders comparisons difficult. The form and particularly 

 the venation warrant the reference of this form to the Apocynaceae 

 which has a large number of shrubs, trees, and leaves in tropical 

 South America. A number of genera prominent in the South Ameri- 

 can flora such as SJcytanthus, Aspidosperma, Tahernaemontana, Val- 

 lesia, Thevetia, Prestonia, Forsteronia, Rohhia, etc., have some species 

 with leaves that are very similar to the fossil. 



Coty pes. —Ceit. No. 35115, a, h, c, U.S.N.M. 



