788 Order 156.—GRAMINEiE. 



sheaths ciliate ; pan. of remote, short (6"), dense, alternate spilces, the rachis flex- 

 uous - glumes nearly equal, both awned; lower pale with a stout awn which is 

 much longer than those of the glumes; upper pale minute; fertile fl. lanceolate. — 

 Dry shades, Car. to Ga. and La. Aug. — Oct. (Panicum, L.) 



20. SETA'RIA, Beauv. Bristly Fox-tail Grass. (Lat. seta, a 

 bristle.) Spikelcts, &c. as in Panicum, but each subtended by a cluster 

 of awn-like bristles (abortive pedicels), forming a sort of bristly invo- 

 lucre, — Fls. in dense, cylindric spikes or spike-like panicles. 



§ Bristles of the involucre rough backwards, in pairs, short No. 1 



§ Bristles rough upwards.— Fertile pales strongly rugous crosswise Nos. 2, 3 



— Fertile pales smoothish, striato lengthwise No. 4 



— Fertile pales smoothish, not striate Nos. 5, C 



1 S. verticillata Beauv. Culm smooth, about 2f high ; lvs. lance-linear, rough- 

 edged ; sheaths smooth, hairy on the margin ; spicale pan. composed of short, 

 divided branches in interrupted verticils, 2 — 3' long ; bristles of the invol. in pairs, 

 rough backwards, as well as the upper part of the culm ; palea? of the 5 roughish- 

 punctate. — ©Sandy fields, N. Eng. to Ohio, more frequent South. July. § 



2 S. glauca Beauv. Bottle Grass. Culm 2 — 3f; lvs. lance-linear, carinate, rough, 

 hairy at base ; sheaths striate, smooth ; ligules setous ; spike cylindric, yellowish- 

 green, 2 — 4' long, nearly simpl-e ; invol. of G — 10 fascicled, scabrous bristles much 

 longer than the "spikelets ; fertilo pale, transversely rugous. — © Fields and road- 

 sides, N. Eng. to Ohio. Jl., Aug. 



/3. purpurascexs. Sheaths and spikelets pilous, awns purple. 



3 S. corrugata Schul. Culm terete, 2 to 3f ; lvs ; linear, 8 to 12' by 3 to 4", 

 very scabrous, as well as the sheaths ; ligules setous ; pan. terete, dense, spike- 

 like, 3 to 6' long, compounded of many oppressed spikes, each of many spikelets; 

 bristles as many as spkls. (one at the base of each) and 3 or 4 times as long ; 

 caryopsis and its pales strongly corrugated (Elliott). — Savannah (Baldwin). 



4 S. viridis Beauv. "Wild Timothy. Culm smooth, 2 — 3f ; lvs. lanceolate, flat, 

 minutely serrulate ; sheaths striate, hairy on the margin, and with a setous stipule; 

 spike 1 to 3' long, cylindric, compound, terminal, green ; involucre of 4 — 10 fas- 

 ciculate bristles, much longer than the spikelets; paleseof the perfect flower longi- 

 tudinally striate, punctate, and minutely corrugated under a lens. — © Common in 

 cultivated grounds, Northern States. July, Aug. 



5 S. Italica Kunth. Culm somewhat Compressed, about 4 to 6f high; lvs. lan- 

 ceolate, 1 — 2f long, an inch wide; sheaths roughish, pilous at the throat; spike 

 compound, interrupted at the base, nodding, G — 8' long sometimes 12 to 18' long 

 and 1' thick (Feay) ; spikelets conglomerate ; invol. of 2 or more bristles, several times 

 longer than the flower ; fertile fl. polished, shining, \" long. — © Ditches, Mid. and 

 S. States. July. 



6 S. Germanica Beauv. Millet. Bengal Grass. Culm 2 — if high, simple, 

 leafy ; lvs. lance-linear, flat, acuminate, serrulate on the margin ; sheaths striate, 

 close, pubescent; stip. bearded; spike compressed, yellowish, oblong-cylindric ; 

 rachis densely hirsute ; involucrate bristles 4 — 8, as long as, or longer than the 

 spikelets, yellowish; glumes unequal, ovate; $ paleoz 1" long, obscurely 3-veined, 

 dull with minute corrugations. — © In fields, often cultivated. § (S. Italica p. 

 Kunth.) 



21. CENCHRUS L. Burr Grass. (Gr. Kevxpog, the ancient name 

 of the millet.) Flowers racemous or spicate ; involucre burr-form, 

 laciniate, echinate, persistent, and becoming hard in fruit, including 

 1 — 3 spikelets; glumes 2, 2-flowered, outer smaller; flowers dissimlar, 

 the lower sterile, the upper perfect; scales 0; branching; spikelets 

 sessile. 



1 C. tritmloides L. St. 1 — 2f long, erect or procumbent and geniculate at 

 base ; lvs. lance-linear, conduplicate, gradually acuminate, 3 — 5' by 2 — 3" ; sheaths 

 open, about as long as the colored joints; spike with the burr-like involucres 

 approximate ; invol. cartilaginous, beset externally with many sharp, retrorsely 



