165 



BROMUS COMMUTATUS. 



ScHEADEE. Koch. Paeneli,. H. Watson. Hookek and Aenott. 



PLATE LV. 



Serrafalcus commutatus, Paelatoee. Babington. 



27ie Tumid Field Brome-Grass. 



Bromus — Pood. Commutatus — Changed. 



A SOMEWHAT common species, growing in corn-fields and on 

 road-sides. 



Stem upright, circular, smooth, and striated, carrying four or 

 fi.ve flat, soft, sharp-pointed leaves, with striated sheaths, the 

 upper sheath having an obtuse ragged ligule at its summit. 

 Joints five. Inflorescence usually simple-panicled. Panicle when 

 young upright, when more mature pendant. Branches rough. 

 Spikelets linear-lanceolate, brownish purple, mostly of ten awned 

 florets. Calyx consisting of two almost equal, broad acute 

 glumes J margin membranous. Upper half of the keels dentate. 

 Outer glume three-ribbed; inner glume seven-ribbed. Florets 

 of two nearly equal-sized palese, the exterior one of basal floret 

 oval, rough, glossy, and somewhat longer than the glumes j 

 seven-ribbed. Inner palea linear-oblong, having two green mar- 

 ginal ribs fringed with white hairs. Stigmas plumose. Length 

 from nineteen to thirty-six inches. Koot fibrous and annual. 



Bromus secalinus is more linear and longer. 



