AGROSTIDEAE 5S 



The Needle Grasses of the gemis Aristida occur all 

 over the State and are easy to recogni^.e. They all agree 

 (except one species) in having the s 'ale (glume) which 

 surrounds the seed prolonged into a tliree pronged beard 

 (awn ) the subdivisions of which are an nu h or two long, slen- 

 der and divergent when the seed is ripe The single exception 

 has one tolerably long awn and the othei two are very short 

 or entirely absent. The base of the "s(ed" is very sharp 

 pointed and has a tuft of rather si iff hairs. The peculiar 

 arrangement of the awns, the poin' and the tuft of hairs 

 doubtless have considerable to do w'th the distribution of the 

 plant, probably being instrumental in scattering and plant- 

 ing the seeds. 



Speaking generally of the \vhole genus (which has a 

 rather large luimbcr of s]:)ecies) it is correct to say that they 

 deserve the common name often given them of "Poverty 

 grass" because they are not valu ible as forage and because 

 tlieir presence in abundance on cUiy area indicates a dearth 

 of good feed. They are presenf in abundance only where 

 better grasses have been killed out or where tlie climatic and 

 soil conditions are so unfavorable that other and better 

 species will not grow. They a' e very rarely eaten by stock, 

 possibly because they are not pilatable, but much more prol>- 

 ably because the "seeds" are very spiny and penetrate the 

 tongues of the animals. 



Most of them are b : ich grasses, in the sense that 

 they form more or less con" | .irt tufts and spread verv little. 

 All except one of our spec'. -• are perennials and thev occur 

 everywhere throughout the State except at very high alti- 

 tudes, thougli they are miu'h more common on the hotter 

 plains. The annual specie.^" (Aristida bromoides) frequently 

 covers large areas after th«.' summer rains, but its dominance 

 in an area tells at once that the better grasses have been eaten 

 out and that this species is present in such abundance because 

 it has been assisted in gaining a foothold by the destruction 

 of the economically much better species. 



