54 AGROSTIDEAE 



Another one of the needle grasses that is easily 

 recognized is the one with very long beards called Arisiida 

 longiseta. In New Mexico this species is usually about 8 

 inches to 1 foot high growing in a very dense tuft with many 

 erect stems and numerous slender curled leaves. The heads 

 are rather slender, the beards are about 2 inches or more 

 long, colored a reddish purple when in full flower, and the 

 two chaffy glumes which enclose the "seed" are of very 

 unequal length, the longer reaching above the base of the 

 spreading awns. The Latin name for this is particularly 

 appropriate as it certainly is the Long-awned Needle 

 Grass. It is very common on some parts of the range since 

 it is a very hardy and resistant plant ; but it is of little or no 

 value as feed for the reason mentioned above. 



Two species with widely spreading rigid stems and 

 panicles occur commonly on the sandy land especially at the 

 south end of the State. They look very much alike but one 

 of them has three awns about an inch long and the other has 

 but one. The plants frequently coyer an area of more than a 

 square foot and are a foot high. 



The commonest species are Aristida purpurea, the 

 Purple Needle Grass^— which isn't always purple, not- 

 withstanding its name — and the Arizona Needle Grass 

 {Aristida arisonica). Both of these form close tussocks from 

 six to ten inches in diameter with numerous narrow tough 

 leaves six to eight inches high with many erect, stiff, slender 

 stems and strict panicles of rather numerous spikelets. The 

 awns are from an inch to an inch and a half long, sometimes 

 quite purple but mostly greenish or yellow if old. They 

 differ from each other in the size and shape of the empty 

 glumes surrounding the "seed," as is described in the treat- 

 ment of the genus -which follows. There are several other 

 species mpre or less common all of which closely resemble 

 each other, and are hard to tell apart. 



