STANDLEY ALLIONIACEAE OF MEXICO. 419 



Stems glabrous above or at least not glandular upon the 

 branches of the inflorescence; clusters of flowers 

 and fruit only 2 to 6 mm. broad, often only 4 or 5 

 flowers in an umbel. 



Stems neither hirsute nor villous below 5. B. sonorae. 



Stems more or less hirsute or villous below. 



Stems nowhere viscid, more or less hirsute, es- 

 pecially about the nodes, upon the peti- 

 oles, and margins of the leaf blades 6. B. hirsuta. 



Stems densely viscid-hirsute below 7. B. Ixodes. 



Annuals. 



Inflorescence spicate. 



Anthocarp about as broad as long. 



Stems densely villous and viscid; leaves not black- 

 dotted beneath; bracts persistent; anthocarp 



4-angled 8. B. urightii. 



Stems viscid only in rings about the middle of the 

 internodes; leaf blades black-dotted beneath; 



bracts deciduous; anthocarp 5-angled 9. B. fallax. 



Anthocarp usually twice as long as broad. 



Stems densely viscid throughout 10. B. spicata. 



Stems not densely viscid, glabrous at least above. 



Anthocarp truncate at the apex 11. B. rosei. 



Anthocarp rounded at the apex. 



Perianth 1 mm. long or less; stamens in- 

 cluded. (Spikes very slender and 

 few-flowered.) 

 Ribs of the fruit broad and smooth; 



stems glabrate; leaf blades thin. 12. B.watsoni. 

 Ribs of the fruit narrow and rugulose; 

 stems viscid-puberulent; leaf 



blades thicker 13. B. torreyana. 



Perianth 1.5 to 3 mm, long; stamens 

 usually exserted. 

 Spikes densely flowered; ribs of the 



fruit thin (perianth 3 mm. long). 14. B.xanti. 

 Spikes with but few flowers, slender, 

 the flowers remote; ribs of the 

 fruit thick and smooth. 

 Perianth 3 mm. long; leaf blades 



black-dotted beneath 15. B. alamosana. 



Perianth 1.5 mm. long; leaf blades 



not black-dotted beneath. . 16. B. coulteri. 

 Inflorescence not spicate. 



Anthocarp rounded at the apex, subtended by large, 



reddish, persistent bracts 17. B. purpurascens. 



Anthocarp truncate or retuse at the apex; bracts small, 

 greenish or whitish, early deciduous. 

 Anthocarp with 5 conspicuous, thin wings, about as 



broad as long, retuse at the apex 18. B. alata. 



Anthocarp not with thin wings, angled, the angles 

 sometimes so broad as to be almost wing-like, 

 truncate at the apex. 

 84645°— vol 13, it 11—11 4 



