18 POACEAE. 



pubescent. S., especially along the Susquehanna. Bather rare in woods. 

 Schists. Sum. and fall. 



22. P. Ashei G. Pearson. Stems tufted, 2-4 dm. tall, erect, usually sparingly 

 branched, rarely much branched and prostrate, puberulent: leaf -blades lanceo- 

 late, sparsely ciliate at the base, with long hairs, usually 5-8 cm. long, 6-10 mm. 

 wide, a little cordate at the base, the upper blades about the same length, the 

 lower ones shorter, the early basal blades ciliate: panicle 57 cm. long: spike- 

 lets about 2.3 mm. long and about 1 mm. wide, elliptic. Lower Susquehanna 

 valley. Eather rare, in woods. Schists. Sum. 



23. P. latifolium L. Stems 3-9 dm. tall, erect, simple, or somewhat branched 

 above: leaf -blades 7-18 cm. long, 2-4 cm. wide, cordate-clasping at the base, 

 acuminate, ciliate: panicle 8-15 cm. long: spikelets 3-4 mm. long, turgid, oval 

 to obovoid, pubescent. Frequent, in woods. Sum. 



24. P. clandestinum L. Stems tufted, 6-14 dm. tall, the branches clothed with 

 the papillose-hispid overlapping leaf -sheaths : leaf -blades ciliate at the cordate 

 and clasping base, the primary ones 12 dm. long, 1.52.5 cm. wide, acuminate, 

 lanceolate, those on the branches ovate-lanceolate and usually less than 1 dm. 

 long: primary panicle long-exserted, 912 cm. long, broadly ovate, the later 

 panicles wholly or partially concealed in the sheaths: spikelets 2.73 mm. long 

 and about 1.3 mm. wide, elliptic, pubescent with spreading hairs. M. S. 

 Eather common, in moist soil. Limestones, schists. Sum. 



25. P. Boscii Poir. Stems tufted, erect, pubescent or glabrous, finally branch- 

 ing: leaf -sheaths glabrous, or softly pubescent; blades ovate-lanceolate, cordate 

 and clasping at the base, glabrous or pubescent, 6-12 cm. long, 2^4 cm. wide: 

 panicle 6-12 cm. long: spikelets 4-6 mm. long, 1.5-2 mm. wide, the scales dis- 

 tant, pubescent with long weak hairs. Eather common, in woods. Sum. 



9. CHAETOCHItOA Scribn. Annual or perennial grasses, with usually 

 flat, sometimes complanate, leaf -blades and dense terminal cylindric spike-like 

 or narrowly thyrsoid panicles. Spikelets with one or a cluster of 2-several 

 sterile barbed bristle-like persistent branches. Scales 4, the 3 outer membranous, 

 the first often very short and together with the larger second one empty, the 

 third scale frequently longer than the second, empty, or rarely enclosing a palet 

 and also sometimes a staminate flower, the fourth scale usually shorter than the 

 spikelet, chartaceous, glabrous, shining, often transversely rugose, finally indu- 

 rated, obtuse, enclosing a shorter palet of similar texture and a perfect flower. 

 Stamens 3. Styles distinct, elongate. Stigmas plumose. [Setaria Beauv., 

 not Achar.] FOXTAIL. FOXTAIL-GRASS. 



Inflorescence with the spikelets racemosely arranged : bristles 5-16 at the base of 



each spikelet, involucrate. 1. C. glauca. 



Inflorescence with the spikelets in clusters or on branches : 



bristles 1-3 at the base of each spikelet, not involucrate. 



Bristles downwardly barbed. 2. C. verticillata. 



Bristles upwardly barbed. 



Panicle usually 1 cm. thick or less : bristles commonly 



green : spikelets about a mm. long. 3. C. viridis. 



Panicle usually 2-3 cm. thick : bristles usually purple : 



spikelets 2.5-3 mm. long. 4. C. italica. 



1. C. glauca (L.) Scribn. Stems tufted, 3-12 dm. tall: leaf -blades 1.5 dm. 

 long or less, 4-8 mm. wide, glaucous, at least the lower ones pilose near the 

 base on the upper surface: racemes dense, about 1 cm. in diameter, 2-10 cm. 

 long: spikelets broadly ovoid, 3 mm. long and 2 mm. wide, the acute flowering 

 scale striate, coarsely transversely rugose. Common, in waste and cultivated 

 grounds. Nat. of Eu. Sum. PIGEON-GRASS. 



