532 CONTRIBUTIONS FEOM THE NATIONAL HERBARIUM. 



and, externally, as a counter irritant, especially in the treatment of chronic 

 rheumatism. One of the Australian species is reported to be a violent con- 

 vulsive poison, and is said to be used by the natives for poisoning fish. 



Leaves even-pinnate. 



Sepals and petals each 4 or 5 19. Z. microcarpum. 



Sepals and petals each 3. 



Follicles 4 to 4.8 mm. long, blackish ; marginal glands of the leaflets obsolete. 



1. Z. pringlei. 

 Follicles 5 to 7 mm. long, brown ; marginal glands of the young leaflets con- 

 spicuous 2. Z. procerum. 



Leaves odd-pinnate. 

 Leaflets rounded or very obtuse at apex, small, 1.5 cm. wide or narrower. 



Leaflets 3 3. Z, liebmannianum. 



Leaflets 5 or more. 



Leaflets 25 to 61 4. Z. elegantissimum. 



Leaflets 5 to 17. 



Flowers in short, often lateral spikes or spikelike racemes. 

 Follicles 3.5 to 4 mm. broad, the stipe usually long and slender. 



5. Z. fagara. 

 Follicles 4 to 5.5 mm. broad, the stipe short and stout_-6. Z. aflBne, 

 Flowers usually in terminal or lateral panicles or in long slender 

 racemes. 



Calyx of oblong or ovate, distinct sepals 7. Z. purpusii. 



Calyx of triangular or suborbicular lobes, persistent. 



Leaflets 7 to 15; follicles 5 to 7 mm. long 8. Z. insulare. 



Leaflets 5 or 7 ; follicles 3.5 to 4 mm. long 9. Z. culantrillo. 



Leaflets acute or acuminate, or, if obtuse, 2.5 cm. wide or larger. 



Sepals 4; leaflets 3 or rarely 5 10. Z. limoncello. 



Sepals 5 ; leaflets 5 or more in most of the leaves. 

 Branches of the inflorescence corky-thickened ; plants glabrous or 

 nearly so. 

 Seeds 4 to 5 mm. long; follicles 4.5 to 8 mm. long; leaflets abruptly 



short-pointed 11. Z. caribaeum. 



Seeds 6 to 8 mm. long; follicles 9 to 15 mm. long; leaflets usually 

 tapering to an acuminate tip. 



Follicles sessile 12. Z. nelsoni. 



Follicles with a slender stipelike base 13. Z. elephantiasis. 



Branches of the inflorescence not corky-thickened ; plants glabrous or 

 pubescent. 



Sepals suborbicular, strongly imbricate in flower 14. Z. bijugum. 



Sepals oblong or ovate, not strongly imbricate in flower. 



Leaflets glabrous 15. Z. melanostictuin. 



Leaflets more or less pubescent beneath. 



Calyx of distinct sepals, deciduous 16. Z. mollissimum. 



Calyx of united sepals, persistent. 



Follicles 6 to 8 mm. long ; pedicels stout ; leaflets 9 to 14 cm. 



long 17. Z. goldmani. 



Follicles 4.5 to 5.5 long ; pedicels slender ; leaflets 5 to 7.5 cm. 

 long 18. Z. arborescens, 



1. Zanthoxylum pringlei S. Wats. Proc. Amer. Acad. 26: 134. 1891. 



Known only from the type locality, Tamasopo Canyon, San Luis Potosl. 



Tree, sometimes 13 meters high, the trunk 30 cm. in diameter, grayish, 

 armed with short stout spines ; leaflets 4 to 10, oblong, 3 to 7 cm. long, acute 



