52 . POACEAE 



5. S. flexuosus (Thiirb.) Rydb. Tufted perennial; stem 3-8 dm. high; 

 leaf-blades 5-2U cm. long, 2-4 mm. wide, usualh' flat, somewhat scabrous above; 

 inflorescence 2-4 dm. long; branches 3-6 cm. long, spreading or reflexed; spike- 

 lets about 2 mm. long, usually lead-colored; empty glumes lanceolate, somewhat 

 scabrous. "Sandy soil: Tex. — Nev. — -Ariz.; Mex. Son. Jl-S. 



6. S. cryptandrus (Torr.) A. Gray. More or less tufted perennial; stem 4- 

 10 dm. long, erect, glabrous; leaf-blades 7-15 cm. long, 2-4 mm. wide, flat, glab- 

 rous beneath, scabrous above; panicle 1.5-2.5 dm. long; spikelets lead-colored, 

 2-2.5 mm. long; glumes scabrous on the keel. Sandy soil: Mass. — Pa. — -Ariz. 

 — Wash.; Mex. Plain — Submont. Au-0. 



7. S. heterolepis A. Gray. Tufted perennial; stem 3-10 dm. high, erect; 

 leaf-blades involute, glabrous, with rough margins and midribs, 2-5 dm. long; 

 panicle 7-25 cm. long, open, exserted; branches ascending; glumes smooth and 

 glabrous, the first one subulate, 2-3 mm. long, the second lanceolate, 4-5 mm. 

 long, awn-pointed; lemma obtuse or acute. Dry soil: Que. — Pa. — Tex. — S.D. 

 — Sask. Plain — Suhmont. Au-S. 



8. S. asperifolius (Nees & Meyen) Thurb. Perennial with a cespitose 

 creeping rootstock; stem 1-5 dm. high, erect from a decumbent base; leaf-blades 

 2.5-10 cm. long, 2-3 mm. wide, flat, very scabrous above; panicles 7-20 cm. long, 

 usually included at the base; branches usuallj' spreading in age; spikelets 1.5 

 mm. long; glumes acute, glabrous, somewhat scabrous; lemma slightly exceeding 

 them. Sandy or dry soil: Sask. — Mo. — Tex. — Calif. — B.C.; Mex. Plain — -Suh- 

 mont. Je-S. 



9. S. texanus \'asey. Tufted perennial, otherwise resembling »S'. asperifolius; 

 stems rigid; leaf -blades 2.5-7.5 cm. long, scabrous above; panicle half the length 

 of the plant, included in the sheath below; lower glume half as long as the second 

 one, which is fully as long as the lemma. Plains: Tex. — Okla.^s Colo. — -N.M. 

 Son. 



10. S. confusus (Fourn.) Vasey. Tufted annual; stem 1-3 dm. high, slender, 

 branched below; sheath.s short, loose, glabrous; leaf-blades 1-4 cm. long, 0.5-1.5 

 mm. wide; panicle open, 3-20 cm. long; branches spreading; spikelets 1-1.5 

 mm. long; empty glumes shorter than the lemma, glabrous or pubescent ; lemma 

 pubescent. Meadows especially in sandy soil: Neb. — ^Tex. — Ariz. — Ida.; Mex. 

 Son. — Submont. Jl-S. 



28. POLYPOGON Desf. Beard-grass. 



Annuals or rarely perennials. Inflorescence a dense, contracted, spike-like 

 panicle. Spikelets articulate below the empty glumes, crowded, 1-flowered. 

 Flowers perfect. Empty glumes about equal, each terminating in a slender 

 awn. Lemma thin, emarginate or 2-toothed at the apex, awned or awn-pointed 

 on the back. Stamens 1-3. Styles short, distinct; stigmas plumose. 



1. P. monspeliensis (L.) Desf. Simple annual; stem 1-6 dm. high, erect or 

 decumbent at the base; leaf-blades 4-15 cm. long, 3-6 mm. wide, scabrous; 

 panicle 2-10 cm. long; empty glumes about 2 mm. long, bearing a more or less 

 bent awn 4—6 mm. long; lemma shorter, erose-truncate, hyaline; awn 0.5 mm. 

 long. Waste places: S.C. — N.H.— B.C. — Calif.; Mex.; naturalized from Eurasia. 

 Plain-Submont. Ap-Au. 



29. CINNA L. Reed-grass. 



Tall perennials with broad flat leaves. Inflorescence a large often nodding 

 panicle. Spikelets numerous, 1-flowered, articulate under the emjjty glumes. 

 Flowers perfect. Empty glumes 2, persistent, keeled, acute. Lemma similar, 

 short-awned or awn-pointed just below the apex. Palet 1-nerved, keeled, the 

 keel minutely ciliate. Stamen 1. Styles short, distinct; stigmas plumose. 



1. C. latifolia (Trev.) Griseb. Stem 6-15 dm. high, erect; leaf-blades 1-2.5 

 dm. long, 4-12 mm. wide, scabrous; panicle 1-2.5 dm. long; s{)ikelets 3 mm. long; 

 empty glumes equal, acute, hispidulous on the keel; lemma somewhat shorter, 

 2-toothed at the apex; awTi 1-2 mm. long. Cintia -pcndula Trin. Damp woods: 

 Ne^^.—N.C— Utah— B.C. Submont.— Mont. Jl-S. 



