GRAMINACEiE. 427 



2. (S. glauca Beauv. : spike cylindric ; 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 glato- 

 cum Drmon. 



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

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

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

 Europe. Glaucous Bristle-grass. 



3. S. verticiUata Beauv. : spike subverticillate ; bristles of the involucre 

 in pairs, retrorsely scabrous ; spikelets sohtary ; paleae of the perfect flower 

 roughish-punctate. Panicum verticillatum Lin7i. Penniselum verticilla- 

 tum Nutt. 



Cultivated grounds. Mass. to Del. July. (T). — 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. 0. — Culm 4, (at the South sometimes 

 10,) feet high. Spike ov panicle & — 8 inches long. A naturalized foreigner ; of 

 little value as a grass^ Italian Bristle- grass. 



13. CENCHRUS. Linn.—Bxa 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. echinaius Muhl. 



Dry sandy soils. Throughout the U. S. Aug. (T). — 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 1 -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 stipitate. 

 Scales mostly 3. 



14. ORYZOPSIS. ikf/cA.— Mountain Rice. 

 (From the Greek opv^a, rice, and oipig, resemblance.) 



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

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

 tip. Scales linear-elongated. — Inflorescence panicled. 



1. O. asperifolia Mich. : radical leaves elongated ; sheaths of the cahn 



