GRAMINEAE. 97 



2. Stipa viridula Trin. Green Stipa. (I. F. f. 310.) Culms 4.5-9 dm. tall. 

 Leaves smooth or scabrous, the basal ones involute-filiform, one-third to one-half as 

 long as the culm, those of the culm 7.5-22 cm. long, broader; panicle spike-like, 

 strict and erect; outer scales of spikelet 6-8 mm. long, long-acuminate; third scale 

 shorter, more or less pubescent with long appressed silky hairs, callus acute; awn 

 1.8-3.2 cm. long, bent, loosely spiral at base. Minn, to Br. Col., south to Kans., 

 N. Mex. and Cal. July-Aug. 



3. Stipa avenacea L. Black Oat-grass. (I. F. f. 311.) Culms 3-7.5 

 dm. tall. Leaves involute -filiform, smooth beneath, scabrous above, the basal 

 one-third to one-half the length of the culm, those of the culm 7.5-12.5 cm. long; 

 panicle 1.25-2 dm. long, loose, the branches lax, finally spreading; outer scales of 

 the spikelet 8-10 mm. long; third scale a little shorter, black, pilose at base, and 

 with a ring of short hairs at the top; callus hard, acute; awn 3.75-6.25 cm. long, 

 bent, loosely spiral below. In dry woods, R. I. to Fla. , mostly near the coast; 

 also in western Ont. and Wis. May-June. 



4. Stipa comata Trin. and Rupr. Western Stipa. (I. F. f. 312.) Culms 

 3-6 dm. tall. Uppermost sheaths very long and inflated, enclosing the base of 

 the panicle; basal leaves involute-filiform, one-quarter to one-half as long as the 

 culm, the culm leaves 7.5-1.5 cm. long, a little broader than the basal ones, involute; 

 panicle 1.5-2.25 dm. long, loose, the branches erect-ascending; outer scales of 

 the spikelet I.8-2.4 cm. long, acuminate into an awn 4-8 mm. in length; callus 

 acute; awn 1-2 dm. in length, spiral and pubescent below. On prairies, Alberta 

 to Br. Col., south to Neb., N. Mex. and Cal. June -July. 



5. Stipa spartea Trin. Porcupine-grass. (I. F. f. 313.) Culms 6-12 dm. 

 tall. Basal leaves one-third to one-half as long as the culm, 2 mm. wide or less, 

 usually involute, those of the culm 1.5-3 dm. l° n g> about 4 mm. wide, generally 

 flat; panicle 1-2.5 dm. in length, its branches erect ; outer scales of spikelet 2.5- 

 3.6 cm. long, acuminate into a long slender point; callus acute; awn 1-2 dm. long, 

 stout, usually twice bent, tightly spiral and pubescent below, doubly spiral about 

 the middle. On prairies, Manitoba to Br. Col., south to 111. and Kans. June-July. 



28. ORYZdPSIS Michx. 



Usually tufted grasses, with flat or convolute leaves and paniculate inflorescence. 

 Spikelets i-flowered, broad. Scales 3; the two lower about equal, obtuse or acu- 

 minate; the third scale shorter or a little longer, broad, bearing a terminal awn 

 which is early deciduous, the callus at the base of the scale short and obtuse, or a 

 mere scar. Stamens 3. Styles distinct. Stigmas plumose. Grain oblong, free, 

 tightly enclosed in the convolute scale. [Greek, in allusion to the supposed resem- 

 blance of these grasses to rice.] About 24 species, distributed through temperate 

 and subtropical regions, rarely extending into the tropics. Besides the following, 

 some 7 others occur in the western parts of N. Am. 



Spikelet, exclusive of awn, 2.5-4 mm. long. 



Awn less than 2 mm. long, much shorter than the scale; outer scales 3-4 mm. in 



length. 1. O. juncea. 



Awn 6-8 mm. long, more than twice as long as the scale; outer scales |about 2.5 

 mm. in length. 2. O. micrantha. 



Spikelet, exclusive of awn, 6-8 mm. long. 



Culms nearly naked, leaves all crowded at the base; panicle 5-7.5 cm. long, its 



branches 2.5 cm. in length or less, erect. 3. O. asperifolia. 



Culms leafy to the top; panicle 1.5-3 dm. long; branches 5-10 cm. in length, more 

 or less spreading. 4. O. melaiiocarpa. 



1. Oryzopsis juncea (Michx.) B. S. P. Slender Mountain rice. (I. F. f. 

 314.) Culms glabrous, 1.5-6 dm. tall, erect. Sheaths usually crowded at the 

 base of the culm; leaves smr>oth or scabrous, erect, involute, the basal about one- 

 half the length of the culm, occasionally equalling it, filiform, those of the culm 

 2.5-10 cm. long; panicle 2.5-6.25 cm. long, the branches 1.25-2.5 cm. in length, 

 erect or ascending, the lower half naked; spikelets 3-4 mm. long, the third scale 

 pubescent with short appressed silky hairs, the awn less than 2 mm. long. In dry 

 places, Quebec to Br. Col., Mass.. Penn. and Wis. May-June. (0. Canadensis Torr.) 



2. Oryzopsis micrantha (Trin. and Rupr.) Thurb. Small-flowered Moun- 

 tain Rice. (I. F. f. 315.) Culms glabrous, 3-7.5 dm. tall, erect, slender. 



