Arizona cottongrass, a coarse, leafy perennial also called cotton- 

 top, silky panicgrass, sugargrass, and small feathergrass, is a mem- 

 ber of a small genus of the millet tribe (Paniceae), and is the only 

 common species of the genus oil the western ranges. Most of its 

 common names originate from the silky-cottony appearance of the 

 panicle. The generic name Trichachn,e is from the Greek trick, 

 hair, and achne, chaff, referring to the hairy second glume and sterile 

 lemma. This species, common on the deserts and foothills of south- 

 ern New Mexico and Arizona in the woodland and semidesert types, 

 occurs from Colorado to central Texas and Arizona and south into 

 Mexico. It was originally described from Lower California, a fact 

 imperfectly alluded to in the specific name calif ornica. There is no 

 record of its occurrence in California proper. It frequently is pres- 

 ent on rocky ridges and along the edge of fields, as well as under cac- 

 tus and other shrubs. Although seldom growing in extensive stands, 

 this grass commonly constitutes from 2 to 5 percent of the ground 

 cover in association with gramas (Boutel&ua spp.), three-awns 

 (Aristida spp.), and cane beardgrass (Andropogon barbinodis). 



This plant responds quickly to spring and summer rains, makes 

 rapid growth and thus, although scattered, provides <a considerable 

 amount of highly palatable green forage at an earlier date than 

 most of its associates. However, its season of maximum palatability 

 is short, as the foliage becomes rather hard and tough when the 

 plant stops growing. Consequently, its palatability decreases until 

 the plant greens up again the following spring. The foliage cures 

 on the ground and, generally speaking, the species ranks as both a 

 good winter and summer grass although its winter use depends 

 largely on the presence of more palatable forage. On conservatively 

 grazed range Arizona cottongrass is utilized chiefly while green. 

 It is, however, also a valuable grass in combination with the slower 

 growing grama grasses, its common associates, as livestock will con- 

 centrate on young Arizona cottongrass and thus give the other 

 grasses a better chance to develop. Propagation by rootstocks aids 

 in the perpetuation and maintenance of this species under arid con- 

 ditions and heavy grazing. Although a good seed crop is usually 

 produced, the plant is not an aggressive spreader. 



While reseeding tests have not yet given good results on the open 

 range this species is believed to have good possibilities under favor- 

 able conditions. Wilson x states : 



Of all the native range forage plant seeds tested at the experiment station, 

 this has given the best germination. One sample of Valota sacclmrata (i. e., 

 Trichachne californica) seed tested in October 1930, a little over 10 years after 

 maturity, gave a germination of 92 percent. A percentage of 70 to 85 percent 

 for this species is not uncommon. 



Arizona cottongrass has slender, erect stems 12 to 40 inches high, 

 arising from strong, woolly, knotted rootstocks. The most outstand- 

 ing character is the slender, silky-cottony panicle with its lance- 

 shaped spikelets which grow in pairs and are covered with long, 

 silky white (occasionally purplish) hairs. 



1 Wilson, C. P. THE ARTIFICIAL RESEEDING OF NEW MEXICO GANGES. N. M6X. Agr. Expt. 



Sta. Bull. 189, 37 pp., illus. 1931. 



