SEDGE FAMILY 129 



the margins weakly serrulate. "C. Backii Boott" Fl. Colo. Woods and thick- 

 ets: Colo. — Wyo. — -w Neb. Submonl. Jl. 



19. PoLYTRiCHOiDE.\E Tuckerm. Densely tufted. Culms slender. Leaf- 

 blades narrow. Spike solitary, linear, androgynous, bractless. Rachis straight, 

 not dilated. Perigynia appressed, membranaceous, the upper part empty, 

 oblong-elliptic, many-nerved (not 2-ribbed), compressed-triangular, beakless. 

 Achenes triangular. Style slender, flexuous, its base not enlarged. Stigmas 3, 

 short. 



69. C. leptaleaWahl. Rootstocks elongated; culms 2-6 dm. high, obscurely 

 triangular; leaf-blades 0.5-L25 mm. wide; spike 4-1.5 mm. long, 2-3 mm. wide; 

 perigynia 1-10, 2.5-4.25 mm. long, not concealed by scales. C. polytrichoides 

 A^'illd. Bogs and wet meadows: Lab. — Fla. — Tex. — Colo. — CaUf. — -Alaska. 

 Plain — Mont. Je-Jl. 



20. Obtus.\tae Mackenzie. Rootstocks long, creeping. Culms low, slender. 

 Leaf-blades involute. Sj)ike solitaiy, linear, androgynous, bractless. Perigynia 

 appressed-ascending, ovoid, glabrous, many-nerved, coriaceous, shining, sub- 

 stipitate, obscurely triangular, the beak hyaline-tipped, obliquely cut, at length 

 bidentate. Achenes triangular. Stigmas 3. 



70. C. obtusata Liljebl. Culms 6-20 cm. high, rough above; sheaths spar- 

 ingly filamento.se; leaf-blades 1-1.5 mm. wide; spike 5-12 mm. long, 3-6 mm. 

 wide, the upper two-thirds staminate; perigynia 1-6, impressed nerved, 3-4 mm. 

 long, exceeding the scales. Dry hills and ridges: Mont. — Colo. — -B.C.; Eurasia. 

 Mont. — -Subalp. Je-Au. 



21. NiTiDAE O. F. Lang. Culms slender, leafy at the base. Leaf-blades 

 narrow. Terminal spike linear, staminate. Lateral spikes 1-3, small, pistillate, 

 subglobose to oblong, few-many-fiowered, sessile or short-peduncled. Lowest 

 bract squamiform, sheathless or sub-sheathing. Scales reddish brown with 

 hyahne margins. Perigynia ovoid, turgid-trianguJar, smooth, shining, coriaceous, 

 round-tapering at the base, tipped with the short, cylindric, hyaline-tipped, 

 obliquely cut beak. Achenes sessile, triangular, closely enveloped, short apicu- 

 late. Style short, jointed with the apex of achene, thickish. Stigmas 3, long. 



71. C. supina Wahl. Long-stoloniferous; culms 6-25 cm. high; leaf- 

 blades 1-1.5 mm. wide; pistillate spikes 1-2, sessile, 4-10-flowered, 4-8 mm. 

 long, subglobose or short-oblong; perigynia nerveless (except keels), 2.5-3.5 

 mm. long. Dry soil: Greenl. — -Mack., reported from Minn, and Sask.; Eurasia. 

 Boreal — Arctic. My-Jl. 



22. RupESTREs Tuckerm. Stoloniferous. Culms low. Leaf-blades nar- 

 row, flattened. Spikes 1 and androgynous, or 2-4, with the terminal staminate 

 and linear, the lateral pistillate, approximate or more or less separate, few- 

 flowered, sessile or short-peduncled. Bracts of the pistillate spike leaflet-like, 

 sheathless or nearh' so. Pistillate scales dark chestnut to purplish brown, 

 with hyaline margins. Perigynia appressed-ascending, obovoid, glabrous, 

 membranous, not polished, rounded and sessile at base, 2-ridged, obscurely tri- 

 angular in cross-section, abruptly contracted into a hyaline-tipped, obliquely 

 cut, straight beak. Achenes closely enveloped, triangular, with concave sides, 

 apiculate. Style-base thickened. Stigmas 3. 



72. C. rupestris All. Culms 7-10 cm. high, sharply triangular, rough; 

 sheaths not filamentose; leaf-blades 2-3 mm. wide; spike 1-1.5 cm. long, 3-6 

 mm. wide, the upper half staminate; perigj^nia 6-15, finely many-nerved, 4 mm. 

 long, concealed by the scales. Arctic-alpine situations: Greenl. — Que. — Colo. — • 

 Alta. — Alaska; Eurasia. Alp. — Subalp. Je-Au. 



23. FiRMicuLMES Kiikenth. Culms wiry, triangular, aphyllopodic, the 

 leaf-blades rudimentary at flowering time. Spike 1, androg>mous, the stamin- 

 ate part in age short-peduncled, the pistillate loosely flowered; bracts absent; 

 scales more or less char taceous; perigj-nia 1 to several, obtusely triangular, smooth, 



