1U4 GKAMINEAE (GRASS FAMILY) 



7. P. MiLiXcEUM L. (European Millet.) 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 ; spikelets ovoid, 5 mm. long, turgid. 



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



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



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

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

 long ; leaves 2— A 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 

 flormii!**^"^'' grounds and cultivated fields, Me. to Neb., and southw. July- 

 Spikelet x 3. ^ct. — 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 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 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 vnde, the branches ascending or spreading, 

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

 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 G dm. or more long. Fig. 61. 



Var. obtusum Wood. More slender, 1 m. high or less; leaves ^{- P- yirgatum. 

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



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. — Erect perennials; spikelets lanceolate, pointed, short- 



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

 elliptical, exceeded by the second glume and sterile lemma. 



•*- Eootstocks absent ; plants tufted from a .short caudex, compressed at the leafy 



base, glabrous. 



12. P. longifolium 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 few-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 wliich exceeds the sterile lemma. 



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



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

 loose ; ///rirr/r.s 2-.'!.o cm. long, flat. ().r»-l era. ii'lde ; ])aiiich' often i)nr|ilisli, obloni: 

 ovate, 1.5-3 dm. long, the stiff branches asce)idi)ig, naked at tlie base, with 



