GRAMINACE^:. 427 



2. S. glauca Beauv. : spike cylinclric ; involucre of 6 10 fascicled bris- 

 tles, much longer than the spikelets ; glumes smooth; paleae of the perfect 

 flower transversely rugose. Panicum glaucum Linn. Pennisetum glau- 

 cum Brawn. 



Cultivated grounds. N. Y. and Mass to Car. W. to Ohio. July, Aug. (T). 

 Culm 2 3 feet high. Leaves lanceolate, hairy at base. Spike 2 4 inches long, 

 tawny or orange-yellow ; the rachis angular and hairy. Introduced from 

 Europe. Glaucous Bristle-grass. 



3. (S 1 . verticillata Beauv. : spike subverticillate ; bristles of the involucre 

 in pairs, retrorsely scabrous ; spikelets solitary; palese of the perfect flower 

 roughish-punctate. Panicum verticiUatum Linn. Pennisetum verticilla- 

 tum Nutt. 



Cultivated grounds. Mass, to Del. July. . Culm about 2 feet high, 

 smooth. Leaves lanceolate, acuminate, rough on the margin. Spike 2 3 inches 

 long, composed of interrupted whorls; rachis angled and rough. Introduced 

 from Europe. Rough Bristle-grass. 



4. S. Italica Beauv. : involucre many times longer than the flowers ; 

 spike compound, interrupted at base, nodding ; spikelets glomerate. Pani- 

 cum Italicum Linn. Pennisetum Italicum Nutt. 



Wet grounds. N. J. to Car. July. (T). Culm 4, (at the South sometimes 

 10.) feet high. Spike or panicle 6 8 inches long. A naturalized foreigner; of 

 little value as a grass. Italian Bristle- grass. 



13. CENCHRUS. Linn. Bur Grass. 



(From a Greek word signifying millet ; supposed to have been originally ap- 

 plied to some other plant.) 



Spikelets 2-flowered, 1- 3, enclosed in a laciniate spiny or 

 bristly involucre which is finally hardened. Glumes 2, unequal, 

 membranaceous. Flowers dissimilar ; the lower staminate or 

 neutral ; the upper perfect. Inflorescence racemose. 



C. tribuloides Linn. : involucres globose, pubescent, muricate-spinose, 

 split on one side, enclosing 2 3 spikelets. C. echinatus Muhl. 



Dry sandy soils. Throughout the U. S. Aug. (1). Culm erect or decum- 

 bent, 1 2 feet long, geniculate, branching. Leaves rather short, flat. Spikes 

 about 2 inches long, consisting of 8 10 sessile bur-like heads. A very trouble- 

 some weed. Bur-grass. Hedgehog-grass. 



IV. STIPEJE. Spikelets \-flowered. Lower palea involute, usually 

 indurated in fruit, awned at the tip ; the awn simple or 3-cleft, mostly 

 twisted and articulated at the base. Ovary more or less slipitate. 

 Scales mostly 3. 



14. ORYZOPSIS^ Mich. Mountain Rice. 

 (From the Greek op''", rice, and oil/is, resemblance.} 



Glumes herbaceo-membranaceous, equal, awnless. Palese 2, 

 elliptic, nearly equal, coriaceous, with an articulated awn at the 

 tip. Scales linear-elongated. Inflorescence panicled. 



1. O. asperi folia Mich. : radical leaves elongated; sheaths of the culm 



