11.34 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Leaves simple, or some of them sometimes trifoliolate. 



Fruit 2.5 to 3 cm. long; leaves simple or trifoliolate, if simple long- 



petiolate 6. F. dipetala. 



Fruit 1.5 cm. long ; leaves mostly simple, short-petiolate. 



Leaves broadly rounded at base 7. F. potosina. 



Leaves acute at base 8, F. nummularis. 



Petioles and rachis not winged; leaves pinnate, all or most of them with 5 

 or more leaflets. 



Flowers with petals. Leaves usually sharply serrate 9. F. cuspidata. 



Flowers without petals. 



Wing of the samara equaling or shorter than the body. 



Leaflets glabrous or nearly so ; wing of the samara usually acutish or 



at least narrowed to the apex 10. F. berlandieriana. 



Leaflets finely pubescent I)eneath ; wing of the samara very obtuse or 



emarginate 11. F. velutina. 



Wing of the samara longer than the body. 



Leaflets conspicuously barbate beneath along the costa, even in age. 



12. F. uhdei. 

 Leaflets glabrous beneath or finely pubescent, very inconspicuously if at 

 all barbate. 



Leaflets glaucous beneath 13. F. papillosa. 



Leaflets green beneath or merely glaucescent. 

 Venation of the leaflets prominently reticulate beneath. 



14. F. standleyi. 

 Venation not prominently reticulate, only the lateral nerves con- 

 spicuous 15. F. pringlei. 



1. Fraxinus purpusii T. S. Brandeg. Univ. Calif. Publ. Bot. 4: 90. 1910. 

 Puebla ; type from San Sim6n. 



Small tree, glabrous throughout ; leaflets 5 or 7, ovate-oblong to lanceolate, 

 2 to 5 cm. long, acute, obtuse at base, sessile, coai*sely serrate, thick, lustrous ; 

 flowers apetalous, in very shoi't panicles; samaras 2 cm. long, the wing emar- 

 ginate, longer than the thick body. 



2. Fraxinus greggii A. Gray, Proc. Amer. Acad. 12: 63. 1877. 



Fraxinus schiedeana parvifoUa Torr. U. S. & Mex. Bound. Bot. 166. 1859. 



Coahuila to Tamaulipas and Zacatecas. Western Texas. 



Shrub or tree, sometimes 8 meters high, with a trunk 20 cm. in diameter, 

 the bark thin, gray, scaly ; leaflets usually 5 or 7, sessile, obtuse, glabrous, the 

 margins often revolute; flowers apetalous, in very short clusters; samaras 1.5 

 to 2 cm. long, the wing much longer than the thick terete body; wood hard, 

 close-grained, brown, its specific gravity about 0.79. " Escobilla," " barreta 

 china" (Coahuila). 



The wood is used only for fuel. Palmer reports that in Coahuila the leafy 

 branches are used for making coarse brooms. 



3. Fraxinus rufescens Lingelsheim, Bot. Jahrb. Engler 40: 218. 1907. 

 Type from "Sierra de Gorton" (Veracruz?). 



Shrub or small tree, the branchlets and inflorescence f erruginous-tomentose ; 

 leaflets 7 or 9, sessile, 1 to 1.5 cm. long, 5 to 8 mm. wide, subcoriaceous, gla- 

 brous, paler beneath; panicles 2 cm. long, tbe flowers apetalous; samaras 2 

 to 2.5 cm. long, the wing emarginate. * 



