Black grama, also called woolly-foot grama, is a tufted, long-lived 

 perennial grass. Unlike most gramas it reproduces and spreads 

 vegetatively by means of runners (stolons). Although Griffiths 1 

 states that it is occasionally an annual, under range conditions it is 

 practically invariably a perennial. It is a key species on many 

 Southwestern ranges of lower elevations and has been the subject 

 of more intensive study than most native, western forage plants. 



Black grama ranges from western Texas, through New Mexico 

 and Arizona, south into Mexico. It is characteristically a lower- 

 altitude grass, its main altitudinal range being from 3,500 to 5,500 

 feet, although it is occasionally found a'bove 7,000 feet. It occurs 

 mostly in open grasslands and on dry, gravelly or sandy soils. Origi- 

 nally it occurred almost as a pure type over extensive areas, and is 

 still a dominant plant under favorable conditions. It occurs less 

 commonly in the foothills, being very intolerant of shade, and is 

 found but rarely on clay loams or adobe flats. It is very abundant 

 in portions of the Rio Grande Valley of New Mexico where it occu- 

 pies large stretches of the open, gently sloping country between the 

 rugged upper foothills and the brushy areas of the lower foothills 

 and mesas above the bottom lands. Here, in favorable years, it some- 

 times makes a crop heavy enough to be cut for hay. 



Black grama is a choice forage grass, and was originally the main- 

 stay of the range on numerous areas of the Southwest. It is highly 

 palatable and nutritious both in summer and winter, and makes a 

 valuable year-long range forage plant, especially for cattle. As 

 Nelson 2 points out, the lower parts of the stems remain green dur- 

 ing the milder winters, and clusters of leaves may start growth from 

 some of the stem joints (nodes) in the spring. If it does not remain 

 green, it cures well on the stalk and retains its nutritive value 

 through the dry, spring period when other range forage is unpalat- 

 able or unavailable. 



Although black grama can withstand recurrent grazing by live- 

 stock on heavily used ranges it spreads but little. Too heavy utiliza- 

 tion seriously impairs its vigor and plants so weakened die out during 

 drought periods. Campbell and Bomberger 3 point out that, in 

 parts of the Southwest, black grama is subject to serious depletion 

 as a result of drought or overgrazing, or both. In order to enable 

 this valuable forage grass to maintain its stand its methods of re- 

 production and spreading must be considered when grazing the 

 range. 



Black grama maintains and increases the size of its stand in 

 three different ways, viz (1), by seed production, (2) lateral spread 

 by tillering, and (3) revegetation by stolons from old tufts. On the 

 whole, black grama reproduces very little from seed. Its seed habits 

 are unusually variable and are not dependable. During very favor- 

 able growing seasons a heavy crop of flower stalks and flowers is 



1 Griffiths, D. THE GRAMA GRASSES : BOUTELOUA AND BBJLATED GDNBRA. U. S. Natl. Mus., 

 Contrib. U. S. Natl. Herbarium 14 : 343-444, illus. 1912. 



2 Nelson, Enoch W. THE INFLUENCE OF PRECIPITATION AND GRAZING UPON BLACK GEAMA 

 GRASS RANGE. U. S. Dept. Agr. Tech. Bull. 409, 32 pp., illus. 1934. 



3 Campbell, R. S., and Bomberger, E. H. THE OCCURRENCE OF GUTIERREZIA SAROTHRAE 



ON BOUTBLOHA BRIOPODA RANGES IN SOUTHERN NEW MEXICO. Ecology 15: 49-61, jllUS. 



1934. 



