29. Carex Brittoniana Bailey. 



Tufted perennial: rhizomes 2-4 mm. thick, black-fibrous, with internodes about 



1 mm. long, branching: culms 35-75 (-90) cm. long, 2-2.5 (-3) mm. thick, erect, 

 sharply triangular; sheath venters stramineous-hyaline; blades 2.5-5 mm. broad, 

 flat, shorter than the culms; inflorescence 25-50 mm. long, 10-25 mm. broad, of 



2 to 5 clumped or slightly separated ascending nearly globose to ovoid burlike 

 basally strongly attenuate gynecandrous sessile spikes 11-16 mm. long; bracts 

 essentially absent; perigynia (30 to) 40 to 50 (to 65) per bur, (5.5-) 6-8 (-8.5) mm. 

 long (including the beak), (3.7-) 4-5.5 (-6) mm. broad (including the wings), at 

 maturity divaricate, the body very broadly ovate to very broadly elliptic to nearly 

 orbicular, occasionally broader than long, basally broadly rounded to slightly cor- 

 date, at anthesis thin-membranous, pale-greenish-stramineous, distended only over 

 the achene, at maturity firm to subcoriaceous, plano-convex centrally, stramineous 

 with a submarginal brown zone, ventrally nearly veinless; beak 2.5-3 (-3.5) mm. 

 long, strongly diff'erentiated, at anthesis green, at maturity brown, bidentate; 

 achene lenticular, 2.5 mm. long, 2 mm. wide. 



In wet mud on edge of lakes, ponds and streams, in depressions in fields and in 

 resacas, in Okla. (Waterfall) and in Rio Grande Plains, s.e. and n.-cen. Tex., 

 infrequent in Edwards Plateau, Plains Country and e. Tex., Mar.-May. 



30. Carex reniformis (Bailey) Small. Fig. 263. 



Tufted perennial; culms 2-7 dm. long, 1-2 mm. thick, sharply triangular; 

 sheath venters stramineous-hyaline; lower blades very short, upper ones 1.5-4 

 mm. broad, shorter than the culms; inflorescence (1.5-) 3-4.5 (-5) cm. long, 7-10 

 mm. thick, of 3 to 7 more or less strongly separate gynecandrous erect subglobose 

 apically rounded basally abruptly attenuate spikes 6-10 (-13) mm. long and 5-8 

 (-9) mm. broad; bracts essentially absent; scales half to two thirds as long as their 

 perigynia; perigynia 25 to 40 per spike, erect, (3.3-) 3.8-5 (-5.5) mm. long (in- 

 cluding the beak), (2.3-) 2.6-3.5 (-4.5) mm. broad, broadest near or below the 

 middle, the bodies nearly orbicular to broadly oblong to obovate, winged, at 

 anthesis extremely thin, distended only over the achene, membranous but at ma- 

 turity firm to subcoriaceous, nearly plano-convex or concavo-convex, stramineous 

 or with brownish submarginal staining, ventrally shiny and essentially veinless; 

 beak well-differentiated from body, green turning pale-brownish, 1-1.7 mm. long, 

 bidentate; achene lenticular, 2 mm. long, 1.5 mm. wide. C. brevior (Dew.) Mack. 



Frequent in s.e., e., and n.-cen. Tex., and N.M. (San Miguel Co.), in mud, 

 occasionally in woodlands, usually in open places, Apr-May; e. N.A. w. to B.C., 

 Wash., Ore., Colo., N.M. and Tex. 



31. Carex Hassei Bailey. Fig. 264. 



Rhizomes slender: culms 1-6 dm. tall, sharply triangular, roughened above, 

 overtopping the leaves: leaves clustered near the base, channeled, 2-4 mm. wide, 

 flat above; staminate spike terminal, solitary, peduncled, 6-15 mm. long, often 

 pistillate at apex; pistillate spikes 2 to 4, linear-oblong, 8-20 mm. long, 3.5-4.5 

 mm. wide, the upper spikes approximate and short-peduncled, the lower ones 

 strongly separate and long-peduncled; lowest bract extending beyond the tip of 

 the culm, scales broadly or narrowly ovate, the tips obtuse to acute or acuminate 

 or often aristate with a scabrid awn, all these variations occurring within the 

 same spike, the scales reddish-brown-tinged with green center and narrow hya- 

 line margins; perigynia obovoid, at first greenish or straw-colored, becoming whit- 

 ish and minutely granular, rounded and nearly beakless, the orifice entire; achenes 

 lenticular, 1.5 mm. long, 1.2 mm. wide. 



Along streams, in wet meadows and in bogs, in Ariz. (Navajo and Coconino 

 cos.) ; Alas. s. to Ariz, and Baja Calif. 



515 



