WOOTON AND STANDLEY—FLORA OF NEW MEXICO, 63 
Spikelets small, 10 mm. long or less, the awns 
never more than twice as long as the lemma. 
Panicle strict, congested, never spreading... 7. A. vaseyt. 
Panicle spreading, at least in age. 
Panicles always spreading, the pedicels 
very weak and sinuous; awns 
merely spreading.................. 8. A. micrantha. 
Panicles at first congested, finally spread- 
ing, the pedicels rigid, straight, 
ascending; awns strongly diver- 
gent.......2.2..2002022222 22 eee 9. A. pansa. 
Spikelets large, 15 mm. long or more, the awns 
usually more than twice as long as the 
lemma. 
Panicles simple or nearly so. 
Panicles strict, the spikelets numerous 
and congested, relatively small; 
pedicels short..........-...-..---- 7. A. vaseyi. 
Panicles lax, the spikelets few, scattered, 
about 15 mm. long; pedicels elon- 
gated................5-...-..-----10. A. fendleriana. 
Panicles compound. 
Culms stout; panicles rigidly erect; pedi- 
cels straight...................--- ll. A. wrightii. 
Culms weaker and more slender; panicles 
laxly spreading; pedicels very 
slender, often curved.............. 12. A. purpurea. 
1. Aristida bromoides H. B. K. Nov. Gen. & Sp. 1: 122. 1816. 
, . SIX-WEEKS NEEDLE GRASS. 
Type Locauity: “In montibus regni Quitensis, juxta Tambo de Guamote et 
Llanos de Tiocaxas, alt. 1,600 hexap.”’ 
Range: Texas and Arizona to Mexico; also in South America. 
New Mexico: Santa Fe; Cross L Ranch; Cerrillos; Chama River; Algodones; 
Socorro; Mangas Springs; Black Range; Deming; Dona Ana and Organ mountains; 
White Sands; White Mountains; Guadalupe Mountains; Knowles; Roswell. Dry 
plains and hills, in the Lower and Upper Sonoran zones. 
2. Aristida divaricata Humb. & Bonpl.; Willd. Enum. Pl. 99. 1809. 
Aristida humboldtiana Trin. & Rupr. Mém. Acad. St. Pétersb. VI. Sci. Nat. 5!: 118. 
1842. 
Type Loca.ity: “ Habitat in Mexico.”’ 
Rance: Arizona and western Texas to Mexico. 
New Mexico: Cross L Ranch; Texline; Gallinas Mountains; Black Range; Deming, 
Dona Ana and Organ mountains; Eagle Creek; Lake Arthur. Dry plains and hills, 
in the Lower and Upper Sonoran zones. 
3. Aristida schiediana Trin. & Rupr. Mém. Acad. St. Pétersb. VI. Sci. Nat. 5): 
120. 1842. 
Aristida divergens Vasey, Contr. U. 8. Nat. Herb. 3: 48. 1892. 
TYPE Loca.ity: ‘‘Mexico: prope Jalapam.”’ 
Rance: Arizona and western Texas to Mexico. 
New Mexico: Socorro; Bear Mountain; Copper Mines; Organ Mountains; plains 
south of. Roswell. Upper Sonoran Zone. 
