linear or almost entirely pistillate and oblong, the 1 to 10 perigynia of the lateral 

 spikes widely spreading at maturity; scales broadly ovate, very obtuse, yellowish- 

 brown with broad white-hyaline margins and green center, half the length of 

 the bodies of the perigynia; perigynia concavo-convex, oblong-ovoid to deltoid, 

 2.25-3.25 mm. long, 1.5-2 mm. wide, plump and firm, the body broadest just 

 above the base, thick-margined, olive-green becoming brown, several-nerved 

 dorsally, nerveless to definitely nerved ventrally, rather abruptly narrowed into 

 a sparingly serrulate shallowly bidentate beak about one-third or one-fourth the 

 length of the body, the ventral false suture inconspicuous; achenes lenticular, 

 broadly ovate-orbicular, 1.3 mm. long and about as wide just below the middle. 

 In swampy meadows, calcareous bogs, and on springy banks, at moderate 

 elevations (mostly 7,000-11,000 ft.) in Ariz. (Apache Co.); Lab. to B. C, s. 

 to Pa., Kan., n. Calif, and cen. Mex. 



17. Carex atlantica Bailey. Fig. 261. 



Tufted perennial (internodes of the branching rhizomes less than 1 mm. long); 

 culms 2-5 dm. long, about 1 (-2) mm. thick; sheaths stramineous, tight, ventrally 

 papery, tending to split, the orifice horizontal or shallowly U-shaped; inflores- 

 cence interrupted-spiciform, 3-5 cm. long, 5-8 mm. thick, of 3 or 4 subglobose 

 bractless spikes each with 8 to 20 perigynia (rarely as many as 40) and separated 

 by bare axis internodes 5-14 mm. long, the terminal spike attenuate basally (in 

 the staminate portion), gynecandrous, the rest usually wholly pistillate; scales 

 slightly shorter than the perigynia; perigynial bodies spreading at maturity, 1.5-1.8 

 mm. long, broadly ovate to nearly orbicular, plano-convex, firm, marginally sharp 

 but not winged, shiny, stramineous, with several strong nerves ventrally (use lens), 

 abruptly narrowed to the beak which is linear. 0.7-0.9 mm. long and bidentate; 

 achene lenticular, about 1 .7 mm. long and wide. C incomperta Bickn., C. Howei 

 Mack. 



Infrequent or rare at edge of clear acid streams, edge of lakes, swamps along 

 streams and seepage areas, in Okla. (McCurtain Co.) and in e. and s.e. Tex. 

 (Hardin, Nacogdoches, Cass, Wood, Newton and Tyler cos.), spring; e. N.A., w. 

 to Mich., Ind., Tenn. and Tex. 



18. Carex muskingumensis Schw. 



Cespitose with numerous very leafy sterile culms; fertile culms stout. 5-10 

 dm. tall; principal leaf blades 3-5 mm. wide; spikes 5 to 10, fusiform, pointed 

 at both ends, 15-25 mm. long, 4-6 mm. thick, closely aggregated in a dense 

 cluster 4-8 cm. long; pistillate scales lanceolate, about half as long as the 

 perigynia, pale-brown with hyaline margins; perigynia appressed, lanceolate, thin, 

 7-10 mm. long, about a fourth as wide, finely nerved on both sides, gradually 

 tapering to the beak; achene lenticular, narrowly oblong, 2-2.5 mm. long, 0.8 mm. 

 wide. 



Low woods and wet meadows, swamps and alluvial floodplains, in Okla. (fide 

 Fernald and Gleason); Mich., O. and Ky., w. to Kan. and Okla. 



19. Carex athrostachya Olney. Fig. 262. 



Culms cespitose, 1-8 dm. tall; leaves 2 to 4; blades flat. 1-3 mm. wide, yellow- 

 ish green; head ovoid, 1-2.5 cm. long, the spikes 4 to 20. closely aggregated, 

 the staminate basal flowers inconspicuous; bracts usually well developed, the 

 lowest exceeding the head; scales ovate or lanceolate-ovate, shorter than perigynia, 

 acute or short-cuspidate, brownish with hyaline margins; perigynia ovate-lanceo- 

 late. 3-4 mm. long, light-green, becoming straw-colored or brownish, substipitate, 

 ciliate-serrulate above, tapering into a slender terete brownish-tipped beak, the 

 margins of the orifice hyaline; achenes lenticular, oblong-oval, about 1.5 mm. 

 long and I mm. wide. 



508 



