104 GRAMINEAE (GRASS FAMILY) 



7. P. MiLiXcEUM L. (EuRor-KAN Mii.i.ET.) Culms 2-5 dm. high, erect or 

 decumbent; sheaths papillose-hispid; leaves 1-2.5 dm. long, 2.5 cm. or less 

 wide ; panicle dense, drooping at maturity ; spikelets ovoid, 5 mm. long, turgid. 



Waste places, Me. to Pa., vvestw. to Neb. (Adv. from Eu.) 



* * * DICHOTOMIFLORA. Branching annual, glabrous throughout. 



8. P. dichotomiflbrum Michx. Culms compressed, thick, suc- 

 culent, spreading or ascending from a decumbent base, 3-18 dm. 

 long ; leaves 2-4 dm. long, 8-15 mm. wide, scabrous above ; pan- 

 icles 1.2-4 dm. long, diffuse ; spikelets short-pediceled, mostly 

 secund toward the ends of the branchlets, 3 mm. long, acute ; 

 first glume obtuse, second and sterile lemma pointed beyond 

 the fruit. (P. proliferum Am. auth. not Lam.) Low waste 

 flonSm! '" grounds and cultivated fields, Me. to Neb., and southw. July- 

 Spikclet x 3. 9 ct * Slender, depauperate, erect or prostrate specimens occur 

 in sterile ground. FIG. 60. 



* * # * VIRGATA. Stout simple mostly glabrous perennials, with long-pediceled 

 spikelets and stout creeping rootstocks. 



9. P. amarum Ell. Glaucous, caespitose in large bunches, 5-15 dm. high; 

 leaves crowded at the base, involute, the uppermost exceeding the c</tr<i<-t> 

 panicle, which is 4-8 dm. long, the long slender branches erect; spikelets 4.5 

 mm. long; first glume |-| as long as the spikelet, second glume and sterile 

 lemma pointed beyond the grayish fruit. Sandy seashores, Va., and southw. 

 Aug., Sept. Foliage bitter. 



10. P. amaroides Scribn. & Merr. Glaucous; culms 5-8 dm. high, scattered 

 from a stout creeping rootstock ; leaves 1-3 dm. long, flat or somewhat iitroluti- ; 

 panicle 1.5-4 dm. long, very narrow, the short branches appressed ; .s-/;//,-<7r/s r> 

 mm. long; first glume f as long as the spikelet or more. (P. amarum. var. 

 minor Vasey & Scribn.) Sandy seashores, Ct., and southw. Aug., Sept. 



11. P. virgatum L. (SWITCH GRASS.) Tufted, from strong creeping root- 

 stocks, 0.9-2 m. high, sometimes glaucous; leaves elongated, flat; panicles 1.5- 

 5 dm. long, nearly as wide, the branches ascending or spreading, 



naked at the base ; spikelets 4-4.5 mm. long ; the second ghnne 

 and sterile lemma spreading and pointed, exceeding the fruit. 

 Low open ground or salt marshes along the coast, also on prairies 

 in the interior, Me. to Man., and southw. Very variable ; leaves 

 sometimes pilose above near the base ; marsh plants often very 

 luxuriant, with panicles 6 dm. or more long. FIG. (51 . 



Var. obtusum Wood. More slender, 1 m. high or less; leaves 6 |; ?' 

 not overS mm. wide; panicle 1.5 dm. long or less, rather nar- 

 row; spikelets 3 mm. long; the second glume and sterile lemma blunt a)id 

 scarcely exceeding the fruit. (P. virgatum, var. breviramosum Nash.) Sand 

 barrens, N. Y., N. J., and southw. 



***** AGROSTOIDIA. Erect perennials; spikelets lanceolate, pointed, 

 pcdiceled along the elongated main InDu'ln* ////<> i>iii<-l<' ; fruit 

 elliptical, exceeded by the secouif glume <i<l sterile lemma. 



*- Rootstocks absent ; plant* tnftr<ifrnn> <i sfmrt caudex, compressed at tin- !</>/ 



base, yl brim*. 



12. P. longifblium Torr. Culms slender, 5-lodm. high ; ft-m-cx flat or invo- 

 lute toward the ends, the uppermost often equaling the panicle, 3-5 nrn>. ?''/</, 

 panicle purplish, 1-2.5 din. long, rather fe i"-jl<> ir<>rl; branches solitary or in 

 2's, remote, very slender, finally spreading, naked at the base ; ,sy*//,v/^x 2.8-3 

 mm. Inug ; first glume ' as long as the second which exceeds the sterile lemma. 



Moist sandy .L: round, (M. to I). ('.. and sontliw., mostly coastal. .July-Sept. 



I-".. P. agrostoides Spreim. r////,/.s 1-10 dm. high, ruttu > xtnut : sheaths 

 loose ; Mode* 2-3.6 cm. long, flat, o.r.-i t -m. ?'-/Vr; panicle often purplish, oblong^ 

 ovate, 1.5-3 dm. long, the stiff branches ascendini/. naked at the base, with 



