GRAMINEAE. 



2. Stipa viridula Trin. Green Stipa. 

 (Fig. 310.) 



Stipa I'iridnla Trin. Mem. Acad. St. Petersb. (VI. ) 2: 



1836. 

 Stipa spartea Hook. Fl. Bor. Am. 2: 237. 1840. Not Trin. 



Glabrous, culms i}4-3 tall, erect, simple, 

 smooth. Sheaths shorter than the intern odes; ligule 

 i"-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 

 ^'-itf' long, bent, loosely spiral at base. 



Minnesota to British Columbia, south to Kansas. 

 Mexico and California. July-Aug. 



3. Stipa avenacea L,. Black Oat-grass. (Fig. 311.) 



Stipa ai'enacea L- Sp. PI. 78. 1753. 

 Stipa barbata Michx. Fl. Bor. Am. 1:53. l8 3- 

 Sttpa I'infinica Pers. Syn. 1:99. 1805. 

 Stipa bicolor Pursh, Fl. Am. Sept. 73. 1814. 



Culms glabrous, i-2% tall, erect or leaning, sim- 

 ple, smooth. Sheaths shorter than the internodes ; 

 ligule about \" 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 i%'-2 l /x' 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. (Fig. 312.) 



Stipa comata Trin. & Rupr. Mem. Acad. St. Petersb. 

 (VI.) 5: 75- 1842- 



Glabrous, culms i-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 i // -2 // long, obtuse; leaves 

 smooth or somewhat scabrous, the basal invo- 

 lute-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'-o/ long, loose, the branches $'-$' in length, 

 erect-ascending, naked at base ; outer scales of 

 the spikelet 9"-! 2" long, glabrous, acuminate 

 into an awn 2 // -4 // in length; third scale 4"-6" 

 long, callus acute; awn 4 / -8 / in length, slender, 

 curled, spiral and pubescent below. 



On prairies, Alberta to British Columbia, south to 

 Nebraska, New Mexico and California. June-July. 



