STANDLEY TEEES AND SHRUBS OF MEXICO. 625 



Pistillate inflorescence many-flowered. 



Leaves cuspidate-acuminate, long-petiolate 3. A. schlechtendaliana. 



Leaves acute or obtuse, short-petiolate 4. A. longipes. 



Pistillate flowers sessile. 



Staminate spikes without pistillate flowers, terminal 5. A. longestipularis. 



Staminate spikes with pistillate flowers at base or, if wholly staminate, 

 axillary. 

 Pistillate spikes, at least the well-developed ones, with staminate flowers 

 above or, if not so, the bracts divided into subulate lobes, these ciliate 

 with long gland-tipped hairs. 

 Bracts shallowly lobate or dentate. 

 Bracts glandular-pubescent. 



Teetli of the bracts 9 to 13 32. A. langiana. 



Teeth 17 to 21 6. A. cuspidata. 



Bracts without glandular pubescence. 

 Pistillate bracts minutely 1 to 4-dentate; leaves glabrate, mostly 6 



to 18 cm. long 7. A. diversifolia. 



Pistillate bracts with about 9 short teeth ; leaves densely pubescent, 



2.5 to 3.5 cm. long 8. A. scMumbergeri. 



Bracts divided into long subulate lobes, these ciliate with long gland- 

 tipped hairs. 



Pistillate spikes elongate 9. A. glandulifera. 



Pistillate spikes subcapitate 10. A. arvensis. 



Pistillate spikes without staminate flowers above, the bracts never with 

 subulate and glandular-ciliate lobes. 

 A. Pistillate spikes all axillary. 



Pistillate bracts lobed or cleft to below the middle. 



Bracts 3-lobed 11. A. seleriana. 



Bracts 9 to 17-lobed. 



Lobes of the bracts subulate-linear 12. A. trachyloba. 



Lobes of the bracts lanceolate or broader. 



Pistillate spikes subsessile 13. A. melochiaefolia. 



Pistillate spikes slender-pedunculate. 



Bracts 9 to 11-lobed 14. A. unibracteata. 



Bracts 13 to 17-lobed 15. A. leptopoda. 



Pistillate bracts lobed to the middle or less deeply. 

 Fertile spikes all or mostly 8 to 15 cm. long, the bracts very numerous. 



Stipules lanceolate 16. A. macrostachya. 



Stipules setaceous. 

 Leaves serrate with, somewhat spreading teeth ; bracts shallowly 



dentate .* 17. A. macrostachyoides. 



Leaves with appressed and incurved teeth ; bracts deeply den- 

 tate 18. A. flavescens. 



Fertile spikes 1 to 5 cm. long, rarely longer, with comparatively 

 few bracts. 

 Pistillate inflorescense consisting of a single subsessile bract. 



19. A. rafaelensis. 

 Pistillate infloresence with several bracts or, if of a single bract, 

 this long-pedunculate. 

 Bracts without glandular pubescence. 

 Teeth of the bracts acuminate 20. A. leptoclada. 



7808—23 8 



