MANUAL OP THE GRASSES OF THE UNITED STATES 



551 



FIGURE 1153. Distribution of 

 Anthaenantia rufa. 



glume and sterile lemma about as long as the fruit, 3- to 5-nerved, 

 copiously silky; fertile lemma cartilaginous, lanceolate, acuminate, 

 usually brown, the flat white hyaline mar- 

 gins broad. Perennials with slender erect or 

 ascending racemes, approximate to rather 

 distant along a slender main axis, forming 

 a white to brownish silky panicle. Type 

 species, Trichachne insularis. Name from 

 Greek thrix (trich-), hair, and achne, chaff, 

 alluding to the silky spikelets. 



Trichachne insularis is not relished by cattle, 

 hence the name sourgrass by which it is called in the West Indies; 

 T. californica is a constituent of the ranges of the Southwest, and 

 furnishes fair forage. 



Fruit 4 mm long; spikelets tawny- villous 1. T. INSTJLAKIS- 



Fruit 3 mm or less long (rarely 3.5 mm) ; spikelets white- villous. 



Spikelets long-silky, the hairs exceeding the spikelet; fruit 3-3.5 mm long. 

 Panicle branches stiffly ascending or spreading, comparatively few flowered; 



fruit oblong-lanceolate, gradually pointed 3. T. PATENS. 



Panicle branches appressed, densely flowered; fruit obovate, abruptly 



pointed, the point scarcely indurate 2. T. CALIFORNICA. 



Spikelets short-silky, the hairs not exceeding the spikelet; fruit 2.4 mm 

 long 4. T. HITCHCOCKII. 



1. Trichachne insularis (L.) Nees. SOURGRASS. (Fig. 1155.) Culms 

 suberect from a hard scaly hairy swollen base, 1 to 1.5 m tall; leaves 



numerous; the sheaths sparsely hirsute; blades 

 elongate, 8 to 15 mm wide; panicle 15 to 30 cm 

 long, the slender racemes mostly 10 to 15 cm 

 long, some what nodding; spikelets approximate, 

 excluding the hairs about 4 mm long, the tawny 

 hairs much exceeding them. 21 (Valota insu- 

 laris Chase.) Low open ground and waste 

 places, Florida, Alabama (Mobile), and south- 

 ern Texas; Mexico, West Indies to Argentina. 



2. Trichachne californica (Benth.) Chase. COTTONTOP. (Fig. 

 1156.) Culms erect from a knotty swollen felty-pubescent base, 40 

 to 100 cm tall; leaves numerous, the sheaths glabrous to sparsely 

 pilose; blades mostly less than 12 cm long, 3 to 5 mm wide, from 

 nearly glabrous to densely puberulent; panicle mostly 5 to 10 cm 

 long, the few racemes usually 3 to 5 cm long, occasionally longer, 

 erect or nearly so; spikelets approximate, excluding the hairs 3 to 

 4 mm long, the white to purplish hairs much exceeding them, often 

 spreading, the middle interneryes of the sterile lemma glabrous. 

 91 (T. saccharata Nash.) Plains and dry open ground, Texas to 

 Colorado, Arizona, and Mexico (fig. 1157). 



3. Trichachne patens Swallen. (Fig. 1158.) Culms tufted, 

 erect, 40 to 90 cm tall; sheaths more or less papillose-pilose, the 

 lowermost densely felty pubescent; blades 5 to 15 cm long, 1 to 

 4 mm wide, scabrous; panicle 10 to 18 cm long, the racemes stiffly 

 ascending or spreading; spikelets remote, 4 mm long, densely silky, 

 the hairs exceeding the spikelet; fruit 3 mm long, acute. 91 

 Dry fields, prairies, and roadsides, Texas. 



4. Trichachne hitchcockii (Chase) Chase. (Fig. 1159.) Culms tufted 

 and branching at base, leafy below, slender, 30 to 50 cm tall; sheaths 



FIGURE 1154. Distribution of 

 Anthaenantia villosa. 



