i04 GRAMINEAE (GRASS FAMILY) 



7. P. MiLiXcEUM L. (European Milt.et.) Culms 2-5 dm. high, erect oi 



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

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

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



* * * DicHOTOMirLORA. — Branching annual, glabrous throughout. 



8. P. dichotomifl5rum Micbx. 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 

 ^^* ^flo^rum *°°^** grounds and cultivated fields. Me. to Neb., and southw. July- 

 Spikderx 8, Oct. — Slender, depauperate, erect or prostrate specimens occur 

 in sterile ground. Fig. 60. 



» « « « VirgXta. — 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 contracted 

 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 sterilt 

 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 l-o dm. long, flat or somewhat involute; 

 panicle 1.5-4 dm. long, very narrow, the short branches appressed ; spikelets 6 

 mm. long; first glume | 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 ghime 

 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. 61. 



Var. obtusum Wood. More slender, 1 m. high or less; leaves ^^' J^^J^Jf^^^^' 

 not over 8 mm. wide; panicle 1.5 dm. long or less, rather nar- pi'ee s 

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

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

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



***** AoRosTofDiA. — Ej-ect perennials; spikelets lanceolate, pointed, short- 

 pediceled along the elongated main branches of the panicle ; fruit narroioly 

 elUpticul, exceeded by the second glume and sterile lemma, 



-*■- Rootstocks absent; plants tufted from a short caudex, compressed at the leafy 



base, glabrous. 



12. P. longifblium Torr. Culms slender, 5-10 dm. high ; leaves flat or invo- 

 lute toward the ends, the uppermost often equaling the panicle, 3-5 mm. wide ; 

 panicle purplish, 1-2.5 dm. long, rather fevj flowered; branches solitary or in 

 2's, remote, very slender, finally spreading, naked at the base ; spikelets 2.8-3 

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

 — Moist sandy ground, Ct. to 1). C, and southw., mostly coastal. July-Sept. 



13. P. agrostoides Spreng. Culms 4-10 dm. high, rather stout; sheaths 

 loose ; blades 2-3.5 cm. long, flat. 0.6-1 cm. loidc ; panicle often purplish, oblon^r- 

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



