Obdbr 156.— GRAMINEiB, 9181 



Bubequal, and about equaling the oblong, terete, deciduous, short-stiped 

 flower; lower pale coriaceous, involute, inclosing the caryopsis and tipped 

 with a simple, jointed awn; scales linear-oblong. — 2f Fls. in a slender 

 or spike-like panicle. 



§ Sheaths all leaf-bearing. Stipe of tho flower nearly glabrous, very short Na 1 



5 Sheaths, at least the upper, leafless. Btipe conspicuously bearded Nos. 3,8 



1 O. melanocdrpa Muhl. Culm erect, simple, leafy, 18 — 24'; panicle simple, 

 flexuous, few-flowered ; spikeleta racemoua, ovoid-lanoeolate ; glumes acuminate, 

 mucronate, 5 — 6" in length, smooth; pales hairy, nearly black when ripe, the 

 lower one tipped with au awn an inch in length ; fruit black. — Rocky hills, V. S, 

 and Can., frequent. Aug. (Piptatherum nigrum Torr.) 



2 O. asperifolia Mx. Culm nearly naked, purple at base, 10 — 20'; Ivs. subrad- 

 ical, erect, rigid, pungent at the point, nearly as long as the stem, cauline ones few 

 and very short; spikeleta in a racemous, simple, flexuous panicle, 2 to 4' long, 

 1 — 2 upon each branch ; glumes abruptly acuminate ; pales white, the lower one 

 with a king, bent awn. — Woods, N. States N. to Subarctic Am. Leaves green 

 through the winter. Caryopsis white, about as large as rice, farinaceous. May. 

 (Uraohne Trin.) 



3 O. Canadensis Torr. Culma slender, 9 to 18' high, naked above; lower 

 sheaths bearing rigid, involute-filiform Ivs. ; pan. 1 to 2' loTig, narrow, the branches 

 mostly in pairs; gls. often purplish, 1 to 2" long; pales white, bearded with whit- 

 ish hairs, the awn short and deciduous or wanting. — Eocky woods, N. Eng., to tho 

 shores of L. Superior. May. (Stipa juncea Mx., neo li. S. Canadensis Poir. 

 Urachne Trin. Milium pungens Torr.) 



15. PAS'PALUM L. (Gr. TratTTroAoc, millet ; from the resemblance 

 of the seeds.) Spikelets plano-convex, in unilateral spikes; glumes 

 (apparently) 2, membranous, equal, ovate or orbicular, closely pressed 

 to the fertile flower ; stigmas plumous, colored ; caryopsis coated with 

 the smooth, coriaceous pales. (But theoretically, the lower glume is 

 obsolete and its place supplied by the empty pale of an abortive flower. 

 In Nos. 19 and 20 the lower glume appears, under a lens, as a mere 

 rudiment.) — Spikes linear, the fls. in 2 or 4 rows ; rachis not jointed ; 

 pedicels articulated. 



% Paspaltjm. Spikelets suborbicular, obtuse, crowded. Spikes alternate. (*) 



* Spikes many (7 to 30), with the spikeleta mostly 4-rowed Nos. 1, 2 



* Spikes few (1 to 3), mostly solitary, slender (1" wide), 2 or 8-rowed No.' 3 



* Spikes few ('2 to 6)— with the spikelets in 2 rows, near %" wide Noa. 4, 5 



— with the spikelets in 3 rows, near 8" broad, (a) 



a Leaves very hairy. Culms decumbent Na 6 



a Leaves only ciliate on the margins Noe. 7, 6 



a Leaves very glabrous, margins scabrous Noa 9, 10 



5 DiGiTARiA. Spikelets ovato or lanceolate, acute. Spikes mostly digitate. (**) 



** Itachis ieaf-like, broader than the 2 rows of spikelets beneath it Nos. 11, 12 



** Eacliis narrow, triquetrous or flat, with the spikelets close-appressed. (b) 

 b Glumes {gUuiie and pale) about equal, as long as the flower, (c) 



C Spikelets lanceolate. Spikes in pairs or threes i Nos. 18, 14 



C Spikelets ovato. Spikes 2 to 4 oftener in pairs. Nos. 16— IT 



b Glume scarce half as long as the pale. Spikes 5 to 12, clustered Nos. 18, 19 



** Kachis filiform with the spikelets loose and subremoto. Nos. SO, 21 



1 P. vlrgatum L. Culms decumbent at base, glabrous, 18 to 30'; Iva. broad- 

 linear, rough-edged, 12 to 18' by 5 to 6''; sheaths glabrous, with a hairy throat; 

 spikes numerous (t to 12) ; rachis straigJit {not flexwms), flat, narrower than the 

 i-rowed, dense, orbicular, obtuse spikelets. — 11 Moist soils, S. States, common in 

 the low country. Jl. — Oct. — A very smooth variety is the V. confertum Le Coate. 



/?. puEPUEASOEKS. Culm below, Ivs. and sheaths dark purple. (P. purpn- 

 rascens Ell.) 



2 P. undulatum Poir. "Plant very glabrous; Vas. long and lihear, tomtwhaX 

 carinate; margin scabrous, base ciliate, sheaths glabrous ; spikes many ; rachis 

 flat, glabrous, margins scabrous, narrower than the 2 to 4-rowed spikelets ; lower 

 glume pubescent, upper glume (palea) smooth, transversely plaited near the margins.)" 

 Itunth. Ga. and r'!a, A variety of Ko. C ? (P. plicatum Ux.) 



