46 CYPERACEAE. 



long as the perigynia. This species tends to be dioecious and is sometimes 

 truly so. Common in alkaline soil. 



Carex athrostachya Olney. Stems tufted, 30-60 cm. tall; leaves 2-3 mm. 

 wide, shorter than the stems; inflorescence a dense ovoid straw-colored head 

 composed of 5-20 crowded spikes, these staminate below; lower bracts 2-5, 

 exceeding the head; perigynia lanceolate, spongy at base, the long beak 

 2-toothed, its margins serrulate; scales acuminate, about equalling the peri- 

 gynia. Common in wet places. 



Carex hoodii Boott. Slender, erect, tufted, very smooth, 30-60 cm. high; 

 leaves many, pale, 2-3 mm. broad, snorter than the stems; spikes about 6, 

 densely crowded into an ovoid or oblong head, 1-2 cm. long; perigynia spread- 

 ing, lanceolate, rather thick, 5 mm. long, dark when mature, obscurely nerved, 

 narrowly wing-margined, somewhat stipitate at base, narrowed into a rough- 

 margined beak nearly as long as the body; scales lance-ovate, acuminate, 

 scarious margined, brownish, as long as the perigynia. In moist places, not 

 common. 



Carex pachystachya Cham. Stems tufted, 30-90 cm. tall; leaves flat, 

 flaccid, 3^4 mm. broad, shorter than the stems; inflorescence a dense oblong 

 head 10-12 mm. long, composed of 6-12 crowded sessile brownish spikes; 

 perigynia spreading, ovate-lanceolate, flat, about 4 mm. long, the beak bi- 

 dentate, serrulate on the thin margins; scales acutish, equalling the perigynia. 

 Very common in wet meadows. 



Carex multimoda Bailey. Very similar to C. pachystachya but the head 

 less dense, one or more of the lower spikes clearly separate or if crowded the 

 head oblong; perigynia indistinguishable. Common in the Blue Mountains. 



Carex arcta Boott. Loosely tufted, pale green; stems 20-60 cm. high, 

 smooth or nearly so; leaves pale green, 2.5-4 mm. long, usually larger than 

 the stems; head ovate-oblong, green or brownish, of 5-12 crowded spikes; 

 spikes oblong or ovoid, 6-8 mm. long; perigynia spreading, ovate, somewhat 

 cordate, gradually tapering into the serrulate beak, strongly nerved on the 

 outer face, 2-3 mm. long; scales hyaline, often brownish, acute, shorter than 

 the perigynia. In moist meadows and copses. 



Carex stipata Muhl. Stems 50-100 cm. tall, sharp-angled; leaves flat, 

 6-8 mm. wide, shorter than the stem; sheaths somewhat rugulose on the 

 inner side; inflorescence a dense ovate head of many crowded spikes, 3-5 cm. 

 long, straw-colored or olivaceous, commonly exceeded by the slender lowest 

 bract; perigynia spreading, triangular-ovate, many- nerved, tapering into a 

 long stout 2-toothed beak, whose margins are serrulate; scales much shorter 

 than the perigynia. Moist woods and copses. 



Carex diandra ampla (Bailey) Piper n. comb. ( C. leretiuscula ampla Bailey.) 

 Densely tufted, the slender stems 90-120 cm. high; leaves narrow, 2-4 mm. 

 broad, mostly shorter than the stems; spikes 6-20, brown, in elongated often 

 nodding usually branched inflorescences, 5-12 cm. long; terminal florets stami- 

 nate; perigynia spreading, ovoid, stipitate, nerved at the base on both sides, 3 

 mm. long, the serrulate beak as long as the thick body; scales brown, ovate, 

 acuminate-cuspidate, as long as the perigynia. In boggy places, Latah 

 County, Idaho. 



Carex filifolia Nutt. Wool grass. Densely matted in extensive tufts; 

 stems 10-20 cm. tall; leaves numerous, filiform, about equalling the stem; 

 inflorescence a solitary terminal spike, the upper portion of which is staminate ; 

 perigynium triangular-ovoid, pale below, darker at apex and very minutely 

 pubescent, the short beak with an entire orifice. In dry soil, sometimes very 

 abundant. Exceedingly difficult to plow up. 



