138 GRAMINEAE. 
Glabrous, 
3. Stipa avenacea I, Black Oat-grass. 
Stipa avenacea I,. Sp. Pl. 78. 1753- 
Stipa barbata Michx. Fl. Bor. Am. 1: 53. 1803. 
Stipa Virginica Pers. Syn. 1:99. 1805. 
Stipa bicolor Pursh, Fl. Am. Sept. 73. 1814. 
Culms glabrous, 1°-2%4° tall, erect or leaning, sim- 
ple, smooth. Sheaths shorter than the internodes ; 
ligule about 1’ long, obtuse ; leaves involute-fili- 
form, smooth beneath, scabrous above, the basal 
one-third to one-half the length of the culm, those 
of the culm 3/-5’ long; panicle 5’-8’ long, loose, 
the branches lax, erect or finally spreading, naked 
below; outer scales of the spikelet 4//-5’’ long, 
acute, glabrous; third scale a little shorter, scabrous 
near the summit, black, pilose at base and with a 
ring of short hairs at the top, otherwise smooth and 
glabrous; callus hard, acute; awn 114/-214’ long, 
bent, loosely spiral below. 
In dry woods, Rhode Island to Florida, mostly near 
the coast. Also in western Ontario and Wisconsin. 
May-June. 
4. Stipa comata Trin. & Rupr. Western Stipa. 
Stipa comata Trin. & Rupr. Mem. Acad. St. Petersb. 
(VI.) 5: 75. 
2. Stipa viridula Trin. 
(Fig. 310.) 
sack “er viridula Trin. Mem, Acad. St. Petersb. (VI.) 2: 39. 
1836. 
Stipa spartea Hook. FI. Bor. Am. 2: 237. 
tall, 
smooth, Sheathsshorter than the internodes; ligule 
1//-2’’ long; leaves smooth or scabrous, the basal 
ones involute-filiform, one-third to one-half as long as 
the culm, those of the culm 3/—9’ long, broader; pan- 
icle spike-like, strict and erect, branches appressed ; 
outer scales of spikelet 3//-4’’ long, long-acuminate, 
glabrous ; third scale shorter, more or less pubescent 
with long appressed silky hairs, callus acute; awn 
34/-114/ long, bent, loosely spiral at base. 
Minnesota to British Columbia, south to Kansas, New 
Mexico and California. July—Aug. 
(Fig. 311.) 
2 
Ee} 
(Fig. 312.) 
Glabrous, culms 1°-2° tall, erect, simple, 
smooth. Sheaths usually longer than the in- 
ternodes, smooth or scabrous, the uppermost 
very long and inflated, enclosing the base of 
the panicle; ligule 1/’-2’’ long, obtuse; leaves 
smooth or somewhat scabrous, the basal invo- 
Inte-filiform, one-quarter to one-half as long as 
the culm, the culm leaves 3/-6’ long, a little 
broader than the basal ones, involute; panicle 
6’-9’ long, loose, the branches 3/—5’ in length, 
erect-ascending, naked at base; outer scales of 
the spikelet 9’’-12’’ long, glabrous, acuminate 
into an awn 2’’-4”’ in length; third scale 4’/-6’’ 
long, callus acute; awn 4/—S’ in length, slender, 
curled, spiral and pubescent below. 
On prairies, Alberta to British Columbia, south to 
Nebraska, New Mexico and California. 
Green Stipa. 
