GRAMINEAE. IO; 



Culms 3-9 dm. tall, erect. Leaves involute-setaceous, glabrous, the margins and 

 upper part of the midrib very rough, the basal about three-fourths the length of the 

 culm, occasionally equalling it, those of the culm shorter; panicle 7.5-25 cm. in 

 length, its branches erect or ascending, alternate or subverticillate, the lower 3.75- 

 8.75 cm. long; spikelets 4-5.5 mm. long, the scales smooth and glabrous, the outer 

 unequal, acuminate, the lower subulate, about half the length of the broad second 

 one, often awn-pointed; third scale obtuse or acute, shorter than the second or 

 occasionally equalling it. In dry soil, Quebec to Assiniboia, south to Penn., 111., 

 Neb. and Ark. Aug. -Sept. 



15. Sporobolus Torreyanus (R. & S.) Nash. FLAT-STEMMED DROPSEED. 

 (I. F. f. 356.) Culms 3-6 dm. tall, from a horizontal rootstock, stout, simple, 

 much compressed, smooth and glabrous. Sheaths compressed, overlapping, some- 

 times scabrous at the summit; leaves 1.25-2.5 dm. long, 2 mm. wide or less, 

 folded, slightly rough; panicle 1-2.5 dm. in length, the branches erect or ascend- 

 ing, the lower 5-7.5 cm. long; spikelets about 1.75 mm. long; outer scales sub- 

 equal, obtuse or somewhat acute, smooth and glabrous; third scale obtuse and 

 apiculate, strongly scabrous, slightly exceeding the outer ones. In bogs, L. I. and 

 in the pine barrens of N. J. Sept.-Oct. (Sporobolus compressus (Torr.) Kth. 

 Not Agrostis compressa Willd. ) 



1 6. Sporobolus asperifdlius Nees & Meyen. ROUGH-LEAVED DROPSEED. 

 (I. F. f. 357.) Culms 1.5-4.5 dm. tall, erect from a decumbent and branched base. 

 Sheaths short, crowded and overlapping; leaves numerous, 2.5-8.75 cm. long, 

 2-3 mm. wide at the base, acuminate, strict, often erect, flat, glabrous, smooth be- 

 neath, very rough above; panicle 7.5-20 cm. in length, included at the base, rarely 

 entirely exserted, the capillary branches spreading or ascending, the lower 5-10 cm. 

 long; spikelets occasionally 2-3-flowered, 1.5 mm. long; outer scales subequal, acute, 

 glabrous, sparingly scabrous; third scale obtuse or acute, glabrous, somewhat ex- 

 ceeding the second. Dry soil, Assiniboia to Br. Col., south to Mo., Neb., Cal. and 

 Mex. Aug. -Sept. 



17. Sporobolus Texanus Vasey. TEXAS DROPSEED. Culms 3-6 dm. 

 tall, branching below. Sheaths crowded, the lower ones papillose-hirsute; leaves 

 erect, firm, 4-15 cm. long, 3-5 mm. wide, smooth beneath, very rough above; 

 panicle included at the base, the upper branches finally widely spreading, 5-10 cm. 

 long; spikelets a little exceeding 2 mm. long, on long slender pedicels; scales 

 smooth and glabrous, the first scale narrow, acuminate, less than one-half as long 

 as the second, which equals the third scale. Kans. (according to B. B. Smyth) to 

 Tex. and N. Mex. Aug. 



18. Sporobolus confusus Vasey. Culms tufted, 1-3 dm. tall, slender, from 

 an annual root. Leaves 14 cm. long, 1.5 mm. or less wide ; panicle open, 3 20 cm. 

 long, its slender branches spreading or ascending, the longer 1.5-4 cm. long; 

 spikelets 1.25-1.5 mm. long, on capillary pedicels which are abruptly thickened at 

 the apex, the empty scales shorter than the flowering scale, glabrous or pubescent, 

 the flowering scale usually pubescent, sometimes glabrous. Neb. (according to 

 Rydberg) and Colo, to Tex., Ariz, and Mex. July-Sept. 



19. Sporobolus serotinus (Torr.) A. Gray. LATE-FLOWERING DROPSEED. 

 (I. F. f, 355.) Glabrous and smooth or very nearly so. Culms 1.5-4.5 dm. tall, 

 from an annual root, erect, slender; sheaths short, confined to the lower part 

 of the culm ; leaves I mm. wide or less, slightly scabrous above, flat, the basal 

 one-third to half the length of the culm, those of the culm 5-10 cm. long ; panicle 

 7.5-22.5 cm. in length, the branches capillary, erect or ascending, the lower 

 2.5-6.25 cm. long; spikelets about 1.25 mm. long, the outer scales subequal, 

 obtuse, smooth or sometimes sparingly scabrous ; third scale twice the length of the 

 outer ones, acuminate. In wet sandy soil, Maine to Mich., south to N. J. 

 Sept. -Oct. 



38. POLYPOGON Desf. 



Mostly annual grasses, with decumbent or rarely erect culms, flat leaves and 

 spike-like panicles. Spikelets I -flowered ; scales 3 ; the 2 outer empty, each ex- 

 tended into an awn ; third scale smaller, generally hyaline, short-awned from be- 

 low the apex, subtending a palet and perfect flower ; palet shorter than the scale. 

 Stamens 1-3. Styles short, distinct. Stigmas plumose. Grain free, enclosed \\\ 



