The Flora of the Cayuga Lake Basin 59 



d. Inflorescence of 1-several distant spikes; spikelets suborbicular, blunt, 



smooth. 40. Paspalum 



d. Inflorescence of several branches forming a panicle; spikelets obtuse, acute, 

 or awned, hispid or hispidulous, large. 41. Echinochloa 



c. Branches of the inflorescence not 1-sided and scarcely ever spike-like; spike- 

 lets various, in an open panicle. 42. Panicum 

 a. Spikelets surrounded by an involucre ; inflorescence spike-like. 



b. Involucre of bristles. 4.}. Setaria 



/;. Involucre spherical, prickly, with the spikelets inside. 44. Cenchrus 



Tribe 10. Andropogoneae 

 a. Inflorescence of spike-like parts. 45. Andropogon 



</. Inflorescence an open panicle. 46. Sorghastrum 



Tribe 1. Festuceae 

 1. Bromus L. 

 a. Spikelets 1-2 (2.3) cm. long exclusive of awns ; flowering glumes 7-10 mm. long, 

 often awned or awn-pointed ; rays of the panicle 2-5. 

 b. Flowering glumes broadly elliptical to suborbicular, firm (firm also in no. 5), 

 glabrous or strigose-scabrous ; awn not longer than the body of the glume ; the 

 lower empty glume 3-5-nerved, the upper one 5-9-nerved ; annuals or biennials 

 in cultivated fields and waste places. 

 c. Sheaths glabrous except the lowermost ; flowering glumes 7-8 mm. long, all 

 nearly equal, spreading at maturity with inrolled margins and thus exposing 

 the rhachilla; panicle at maturity loose with spreading branches. 



1. B. secalinus 

 c. Sheaths pubescent; flowering glumes with flat margins, usually remaining 

 imbricated. 

 d. Flowering glumes 7-8 mm. long, all about equal, very broad, scarcely 

 appressed ; awns wanting ; spikelets broadly oval. 2. B. brizaej ormis 



d. Flowering glumes 8.5-9.5 mm. long (the lower ones), conspicuously decreas- 

 ing in size upward, appressed ; awns about equaling the body ; spikelets 

 elliptic-lanceolate. 3. B. commutatns 



b. Flowering glumes narrower, lanceolate to elliptical, thinner (except in no. 5), 

 often very hairy, frequently longer-awned ; annuals or perennials, often in wild 

 situations. 

 c. Awns not exceeding the body of the flowering glume; perennials. 

 d. Lower empty glume 3-nerved; panicle small, 7-15 cm. long; spikelets very 



velvety all over. 4. B. Kalmii 



d. Lower empty glume 1-nerved; panicle small or large; spikelets variously 

 hairy. 

 e. Anthers (2.8) Z-A mm. long; flowering glumes firm and somewhat 

 involute, 3-4 mm. wide, inconspicuously nerved except at the summit, 

 usually hairy over most of the dorsal surface, the pubescence variable 

 in density ; upper nodes usually exserted ; flanges of the sheaths not 

 apparent. 5. B. purgans 



e. Anthers 1-2.5 mm. long ; flowering glumes thin, papery ; lateral nerves 

 prominent to the base. 

 /. Flowering glumes moderately broad, 3.4-4 mm. wide, pubescent over 

 much of the lower part, especially near the margin, the nerves rather 

 strong ; empty glumes usually pubescent ; nodes usually all included ; 

 summit of the sheaths usually with a conspicuous flange and pilose 

 ring; nodes glabrous except in the form with hairy sheaths. 



6, /'. altissimus 



