HOW TO KNOW THE GRASSES 



43b. Spikelets 2 — 4 mm. long, glabrous. Fig. 328. 



BROWNTOP MILLET Panicum iasciculatum Swartz 



Annual; tufted, rather bushy; culms 30 — 100 

 cm. long; leaf blades 6 — 20 mm. wide, gla- 

 brous; ligule of hairs, 1 mm. long; sheaths 

 glabrous or papillose-hairy; panicles 5 — 15 

 cm. long, made up of simple branches 5 — 10 

 cm. long, the spikelets nearly sessile on the 

 branches; spikelets frequently yellowish or 

 brown, 2 — 3 mm. long, with pronounced cross- 

 veins between the longitudinal ones. 



Var reticulatum (Torr.) Beal has pubescent 

 leaf blades, 6 — 10 mm. wide; spikelets 2.6 — 

 3.2 mm. long. 



These plants are common weeds in fields, 

 on river flats, and on waste ground. May — 

 September. 



Figure 328 



44a. Plants without stolons; first glume much shorter than the whole 

 spikelet 45 



44b. Plants producing long, wiry stolons; spikelets very blunt, the first 

 glume nearly as long as the spikelet. Fig. 329. 



VINE MESQUITE GRASS Panicum obtusum H. B. K. 



Figure 329 



Perennial; producing elongated stolons up 

 to 3 m. or more in length, their nodes hairy, 

 swollen; culms erect, flattened, 20 — 80 cm. 

 tall, with glabrous nodes; leaf blades 2 — 7 

 mm. wide, glabrous; Hgules 1 mm. long, 

 membranous; panicles 3 — 12 cm. long, very 

 narrow, with a few ascending branches; 

 spikelets crowded, 3 — 3.8 mm. long, glabrous, 

 brownish; sterile lemma containing a palea 

 and a staminate flower. Banks of streams, 

 ditches, dry wash as, irrigated fields. Vine 

 mesquite furnishes some grazing, especially 

 in the spring. It is sometimes planted for 

 erosion control, especially on terrace outlet 

 channels, spillways of earth dams, and flood 

 plain flats. lune — September. 



171 



