MANUAL OF THE GRASSES OF THE UNITED STATES 97 



10 mm wide, extending into a fine point; panicle 15 to 20 cm long, 

 loose, the distant branches fascicled, ascending, naked below, the 

 lowermost nearly as long as the panicle; spikelets about 8 mm long, 

 the florets approximate; lemmas about 6 mm long. % — Shallow 

 water and marshes, Manitoba to British Columbia, south to northern 

 Iowa, Nebraska, and eastern Oregon (fig. 157); northern Eurasia. 



9. PLEUROPOGON R. Br. Semaphore-grass 



Spikelets several- to many-flowered, linear, the rachilla disarticu- 

 lating above the glumes and between the florets; glumes unequal, 

 membranaceous or subhyaline, scarious at the somewhat lacerate tip, 

 the first 1-nerved, the second obscurely 3-nerved; lemmas mem- 

 branaceous, 7-nerved, with a round indurate callus, the apex entire 

 or 2-toothed, the midnerve extending into a 

 short mucro or into an awn; keels of the palea 

 winged on the lower half. Soft annuals or 

 perennials, with simple culms, flat blades, and 

 loose racemes of rather large spikelets on a 

 slender flexuous axis. Type species, Pleuro- 

 pogon sabinii R. Br. Name from Greek pleura, 

 side, and pogon, beard, the palea of the type im^MgJjg-o of 

 species having a bristle on each side at the base. 



Palatable grasses, but too infrequent to be of economic value. 



Lemmas about 6 mm long; plants annual; spikelets ascending. 



1. P. CALIFORNICUS. 



Lemmas about 8 mm long; plants perennial; spikelets finally reflexed or drooping. 



2. P. REFRACTUS. 



1. Pleuropogon californicus (Nees) Benth. (Fig. 158.) Annual; 

 culms tufted, erect or decumbent at base, 30 to 60 cm tall; blades 

 flat or folded, seldom more than 10 cm long, 2 to 5 mm wide; raceme 

 10 to 15 cm long, with 5 to 10 rather distant short-pediceled spikelets; 

 spikelets 6- to 12-flowered, mostly about 2.5 cm long, erect, or some- 

 what spreading; glumes obtuse, erose, 4 to 6 mm long; lemmas 

 scabrous, 5 to 6 mm long, the nerves prominent, the tip obtuse, 

 scarious, erose, the awn usually 6 to 12 mm long; wings of palea 

 prominent, cleft, forming a tooth about the middle. o — Wet 

 meadows and marshy ground, Mendocino County to the San Fran- 

 cisco Bay region, Calif. 



2. Pleuropogon refractus (A. Gray) Benth. Nodding semaphore- 

 grass. (Fig. 159.) Perennial; culms 1 to 1.5 m tall; blades elon- 

 gate, the uppermost nearly obsolete, 3 to 7 mm wide ; raceme about 

 as in P. californicus, the spikelets as many as 12, about 3 cm 

 long, finally reflexed or drooping; lemmas about 8 mm long, less 

 scabrous and the nerves less prominent than in P. californicus; awn 

 from 12 mm long to nearly obsolete; palea narrow, keeled to about 

 the middle, scarcely or minutely toothed. % — Bogs, wet meadows, 

 and mountain streams, Washington to Mendocino County, Calif., 

 west of the Cascades. 



