606 CLXI. GRAMINE^. Setaru. 



12. P. DICHOTOMUM. 



St. much branched and dichotomous above, erect or decumbent, 1 — 2f 

 high, branches fasciculate ; Irs. linear-lanceolate, smooth, very numerous, 1 — 2' 

 long, ciliate at base ; panicles lateral and terminal, simple, capillar}'^, with loose, 

 spreading branches ; spikclets minute, ovoid-obtuse. — Varies with the stem very- 

 tall, or low, and decumbent ; rather rigid or very slender. N. Eng. to Ky. July. 



13. P. NiTiDUM. Lam. (P. discolor. MuM.) 



St. erect, slender, 8 — 24' high, the nodes with a ring of dense, deflexed 

 hairs ; Ivs. lance-linear, narrow, acuminate, rather remote, 2 — 4' by 2 — 4" ; 

 slicaths as long as the leaves, hairy at the throat and often all over ; stip. ; pan- 

 icle rather small, exserted, roundish-ovoid, ditluse, nearly glabrous, branches 

 spreading ; spikdHs purplish, numerous, small (J" long), oblong, obtuse ; lower 

 glume minute ; abortive Jl. neutral, its outer palea equaling the upper glume ; § 

 white, polished. — 'Zj.^ Woods and fields, U. S. June. 



a. Tall, simple, smooth, except the densely bearded nodes. — Middle and 

 Western States. 



/?. St. with short branches ; Ivs. and sheaths pubescent. — N. Eng. and Middle 

 States, common. 



y. Low, branched, very hairy, purplish. — Dry fields, JN". Eng., common. — 

 These are the extreme forms, between which there are many intermediate ones. 



14. P. MiCRocARPON. Muhl. Darl. 



St. 18 — 30' high, erect, simple, glabrous ; joints glabrous ; Ivs. lanceolate, 

 veined, ciliate at base, undulate and scabrous on the margin, scabrous above, 

 smooth beneath, 6 — 10" wide ; shcatlis deeply striate, smooth; slip. 0; panicle 

 large, much branched, nearly smooth ; spikelets small, numerous, scarcely pu- 

 bescent ; ^ Jloicer as long as the upper glume ; fr. shining, bluish-white. — l^ 

 Woods and low grounds, Penn. Darlington. 



15. P. CAPiLLARE. Annual Pield Panic. 



St. nearly simple, assurgent and thick at base, 1 — 2f high ; Ivs. hairy, 

 broad-linear, acuminate, 4 — 6' long ; sheaths covered with hispid hairs ; panicle 

 large, pyramidal, capillary, loose, expanding ; spikelets small, purple, lanceo- 

 late, acuminate, smooth, on long, hispid peduncles ; abortive fl. of 1 palea. — ® 

 Fields and roadsides, U. S. Aug. 

 p. sylvatictLm. Torr. St. very slender, branched at the base. — Woods. 



16. P. VERRUCosuM. Mulil. (P. dcbilis. Ell.) 



St. slender, decumbent and geniculate, branching from the base, 1 — 2f 

 high ; Ivs. linear, a few inches long, spreading, smooth ; panicle much expand- 

 ed, few-flowered, flowers verrucose ; abortive Jlo^ver of one palea, and neuter. — 

 ® 1 Swamps and thickets. Mid. and S. States. Panicle terminal and lateral, 

 loose and capillary. Aug. 



17. P. VIRGAT0M. Salt-lick Panic. 



Glabrous and often purple ; st. 3— 5f high ; Ivs. long, linear-lanceolate, 

 hairy at base ; sheaths striate ; stip. with long, white cilia; ; panicle virgate, at 

 length spreading, difi'use, very large ; Jls. acuminate, and with the glumes, 

 divaricate, palea; of the abortive flower nearly equal, enfolding the purple sta- 

 mens.— 7). Salt-lick prairies, fields, &c., N. Y. to Ind. ! Aug.— None of these 

 species are of much value in agriculture. 



22. SET ARIA. Palis. 



Lat. seta, a bristle ; from the bristly involucres of the spikelets. 



Inflorescence a compound, cylindrical spike ; spikelets 2-flowered, 

 invested with an involucre of 2 or more bristles ; glumes, flowers, 

 paleae and fruit as in the genus Fanimm. 

 1. S. viRiDis. Palis. Wild Timothy. 



_ St. smooth, 2 — 3f high; Ivs. lanceolate, flat, minutely serrulate; slieaths 

 striate, hairy on the margin, and with a setose stipule ; spike cylindric, com- 

 pound, terminal, green ; involucre of 4—10 fasciculate bristles, much longer 

 than the spikelets ; paka; of the perfect flmver longitudinally striate, punctate.— 

 OD Oommon in cultivated grounds, Free States. July, Aug. 



