96 CHLORIDEAE 



genus Boiiteloiia but here treated under two generic names. 

 Out of the ten species four arc annuals and while they are 

 succulent and palatable when green and fresh, they are of no 

 very great economic importance. Generally speaking the 

 Gramas are found on the drier soils, some species at the lower 

 levels and a few reach altitudes of 7000 feet or even more, 

 especially on high mesa-like plains or plateaus. 



Of the annual species three are referred to as Six- 

 weeks Gramas because they reach maturity in the short rainy 

 season of late summer and early fall. Of these three, one {B. 

 prostrata) occurs in the timbered parts of the mountains above 

 6000 feet, almost all over the State. It is of little importance 

 because it occurs mixed with the many other and better grasses 

 of such localities at a time when they are at tlieir best and 

 thus by comparison sinks into insignificance. The other two 

 species {B. aristidoides and B. polystachya) usually occur on 

 the over-stocked mesas at the lower levels where and when 

 there is little else in the way of food for stock. They thus 

 become of undue importance because they are at once available 

 where nothing else as good is to be had, and are at one and 

 the same time an indicator of the depleted state of a range and 

 the stockman's standby for the summer season. Their seeds 

 are evidently very resistant to dryness or heat and are pro- 

 duced in great numbers ; thus it is that whenever the favorable 

 summer conditions arise, these grasses appear in great 

 abundance, whether there has been a good crop of seeds 

 the previous season or not or even for several seasons. The 

 fourth annual species (B. vestita) is of no very great impor- 

 tance though it grows on sand hills and dunes where other 

 grasses are usually scarce. It is larger than any of the other 

 three annual species and resembles some of the perennial 

 species more closely, but it is not very common nor very 

 abundant at any place where the writer has ever seen it. 



Practically all of the perennial species of Grama are 

 very valuable range grasses though two or three of them 

 are preeminently so. Probably over one third of the total 



