404 GBAMINE^i. (GKASS FAMILY.) 



■»- .4- Spikelets obtuse. 



4. P. SCOparium, Lam. Stem geniculate at the lower nodes and at 

 length branched and reclining: leaves lanceolate, mostly erect and somewhat 

 rigid, hairy beneath and fringed with spreading hairs at base : panicle nearly 

 simple, with slender hairy branches; spikelets few, large, tumid, obovate, usually- 

 hairy : upper glume 9-nerved, twice or three times the length of the lower one : 

 flowering glume with a transverse fold or furrow near the base. — P. pauciflorum , 

 Ell. 1 of Gray's Manual. Colorado, Oregon, and eastward to New England. 



5 P. dichotomum, L. Stem erect and simple, or late in the season 

 decumbent and variously branched : lower leaves usually ovate, the upper linear- 

 lanceolate, smooth or hairy or velvety : terminal panicle open, ovoid, those of 

 the branches short and of en included in the sheaths ; spikelets oblong-obovate, 

 smooth or hairy : upper glume 5 to 7 -nerved, three times the length of the 

 lower one. — Found everywhere, and exceedingly variable. 

 * * Spikelets crowded in 3 or 4 rows or irregularly on the one-sided spike-like 

 branches of the panicle. 1 



4* SET ARIA, Beauv. Bristly Foxtail Grass. 



Annuals, with linear or lanceolate flat leaves. Closely related to Panicum, 

 but easily distinguished by the bristly appearance of the spike. 2 



1. S. setosa, Beauv., var. caudata, Vasey. Stem flattened below, 

 leafy: leaves and sheaths retrorsely scabrous, hairy at the mouth of the 

 sheath, upper leaves involute-pointed : spikes cylindrical, 4 to 6 inches long. 

 often nodding, usually much interrupted below, pale green : bristles up- 

 wardly serrulate : perfect flowers ovate, acute, finely punctate. — Grasses 

 U. S. 13. S. caudata, R. & S. S. W. Colorado (Brandegee) to Arizona, New 

 Mexico, and Texas. 



5. CENCHRUS, L. Bur Grass. Hedgehog Grass. 



Annual. A troublesome grass, in sandy localities, the spiny heads being 

 deciduous and parting readily from the stem. 



1. C. tribuloides, L. Stems branching and ascending: leaves flat: 

 panicle of 8 to 20 spherical heads : involucre prickly all over with spreading 

 and barbed short spines, more or less downy. — Found everywhere, especially 

 on the margins of lakes and rivers. 



1 P. Cnis-fjalli, L. , very widely introduced, possibly indigenous somewhere on the conti- 

 nent, has stems from an inch or two to five feet high, leaves lanceolate and rough on the 

 margins, panicle mostly dense and pyramidal, often tinged with purple, outer glumes rough 

 upon the nerves and abruptly pointed, glume of sterile flower awl-pointed or short-awned, 

 but mostly with a rough awn an inch long or more. —Known as Barn-yard Grass. 



2 The following species, all of which have bristles in clusters and roughened or barbed 

 upwards, are very commonly introduced: — 



5. qlavca, Beauv., known by its dense tawny yellow cylindrical spike (2 to 4 inches long), 

 6 to 11 bristles in a cluster, and perfect flower transversely wrinkled. — Foxtail. 



S. viridis, Beauv., has a green more or less compound nearly cylindrical spike, few bris- 

 tles, and perfect flower striate lengthwise and dotted. —Green Foxtail. Bottle Grass. 



S. Itolica, Kunth, has thick compound yellowish or purplish nodding spikes (6 to 9 

 inches long) and 2 or 3 bristles in a cluster. — Sometimes cultivated under the name of 

 Millet, or Bengal Grass. 



