Bouteloua

All species of Bouteloua (Gramineae) are native to North or South America. The genus Bouteloua includes about 50 C₄ species, both annuals and perennials, divided into two subgenera Chondrosium and Bouteloua, ^{2 14} with a haploid chromosome number × = 10 ^{1 , 3} . Many Bouteloua species have great economic importance because they contribute extensively to the forage supply on range and pasture-land. About 18 species are native to the U.S., showing considerable differences in distribution and in adaptation to the various environments. Of the more economically important species, side-oats grama (Bouteloua curtipen-dula), blue grama (B. gracilis), and hairy grama (B. hirsuta) are species of wide distribution in the western U.S., extending north to Canada and south into Mexico and South America. Slender grama (B. filiformis), black grama (B. eriopoda), and Rothrock’s grama (B. roth-rockii) occur mainly in the southern part of the U.S., extending south into Mexico and South America. ^{2 , 7}