262 



Fig. 256. CATABROSA AQUATIC A (L.) Beauv. Agrost. 157. 1812. (Aim 

 aquatica L. Sp. PI. 64. 1753.) WATER WHORL-GRASS.— A smooth, soft, peren- 

 nial with creeping or ascending culms 2-6 dm. {fO-2°) long, flat leaves and open 

 panicles 5-20 cm. (2'-8') long, the spreading branches in whorls. Sheaths 

 usually overlapping, loose; ligule 3-5 mm. {\h"-2k") long; leaf-blades 2-12 cm. 

 (l'-5')"long, 2-6 mm. (l"-3") wide, flat, obtuse. Spikelets (a, h) 2.5-3.5 mm. 

 (li"-l|") long; empty glumes [c) rounded or obtuse, the first about one-half as 

 long as the second, which is crenulate on the margins; flowering glumes (d) 

 2-2.5 mm. (l"-li'0 long, 3-ner\^ed, erose-truncate at the apex.— In swales and 

 along brooks, often in shallow water, Newfoundland and Labrador, to Quebec 

 and Alaska, south to Nebraska, Colorado, and Utah. (Europe and Asia.) June 

 to August. 



