666 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Fruit pilose. 



Leaflets small, 5 to 10 mm. long 9. R. micropliylla. 



Leaflets large, most of them more than 20 mm. long. 



Bracts of the inflorescence lanceolate or ovate-lanceolate. 

 Leaflets pinnately lobed, densely tomentose beneath. 



10. R. potentillaefolia. 



Leaflets serrate, glabrous or nearly so beneath 11. R. glabra. 



Bracts orbicular or broadly ovate. 



Leaves deciduous; leaflets always 3 12. R. trilobata. 



Leaves persistent ; leaflets 5 or more in all or most of the leaves. 

 Leaflets thick-coriaceous, very lustrous on the upper surface. 

 Leaflets 5 or 7, rarely 9. 

 Leaflets acute or acuminate. 



Lateral leaflets 2 to 3 cm. long 13. R. andrieusii. 



Lateral leaflets 4 to 10 cm. long. 



Leaflets copiously hirtellous beneath 14. R. oaxacana. 



Leaflets sparsely puberulent or glabrous beneath. 



15. R. ciliolata. 

 Leaflets rounded to obtuse at apex, very rarely acute. 



16. R. virens. 

 Leaflets 9 or more in all or most of the leaves. 



Margins of the leaflets strongly revolute 17. P. pacliyrrhacliis. 



Margins of the leaflets not revolute or scarcely so. 



18. R. schiedeana. 

 Leaflets comparatively thin, dull on the upper surface or scarcely 

 lustrous. 

 Laterals leaflets short-petiolulate or nearly sessile. 



19. R. terebinthifolia. 

 Lateral leaflets long-petiolulate. 

 Leaflets usually 11 to 15, 1.5 to 2.5 cm. long__20. R. jaliscana. 

 Leaflets 7 or 9, 3.5 to 7 cm. long 21. R. barclayi. 



1. Rhus laurina Nutt.; Torr. & Gray, Fl. N. Amer. 1: 219. 1838. 

 Lithraea laurina Walp. Repert. Bot. 1: 551. 1842. 



Baja California. Southern California ; type from Santa Barbara. 



Shrub or small tree, sometimes 4.5 meters high, with a broad top, glabrous 

 throughout ; leaves evergreen, long-petiolate, oblong or lanceolate, 7 to 12 cm. 

 long, mucronate, rounded or cordate at base, pale beneath ; flowers white or 

 yellowish, in large terminal panicles ; fruit 3 to 4 mm. long, whitish. 



The plant has the odor of bitter almonds. The seeds yield a pungent oil. 



2. Rhus mollis H. B. K. Nov. Gen. & Sp. 7: 10. pi. 602. 1825. 

 Queretaro, Hidalgo, Puebla, and Oaxaca ; type from QuerStaro. 



Shrub or small tree, 1.5 to 4.5 meters high; leaves nearly sessile, thick- 

 coriaceous, broadly ovate or oval, 3 to 7 cm. long, rounded at apex, usually 

 cordate at base, densely velutinous on the upper surface; inflorescence short 

 and dense ; petals 4 mm. long ; fruit 7 to 8 mm. in diameter. " Zumaque " 

 (Oaxaca, Quargtaro, Hidalgo); " tnu-nd6," " yucu-caya " " sumaco," " sumaco 

 Cimarron" (Oaxaca, Seler). 



3. Rhus ovata S. Wats. Proc. Amer. Acad. 20: 358. 1885. 

 Neostyphonia ovata Abrams, Bull. N. Y. Bot. Gard. 6: 403. 1910. 

 Northern Baja California. California and southern Arizona. 



Shrub ; leaves petiolate, thick-coriaceous, broadly ovate, 5 to 8 cm. long, 

 lustrous, entire ; inflorescence short and dense, puberulent ; flowers pink or 

 v/hite ; fruit about 8 mm. in diameter. 



