120 CYPERACEAE 



date; perigynia ovate, 4.5-5 mm. long, tapering at apex; achenes 1.25 mm. long. 

 Isolated stations on mountain summits: Colo.; Wyo.; Wash. Alp. — Subalp. 

 Au. 



3. Athrochlaexae Holm. Cespitose or with creeping rootstocks. Leaf- 

 blades narrow. Spike solitary, androgynous, bractless, narrow, densely many- 

 flowered. Pistillate scales soon falling. Perigynia slenderly strongly stipitate, 

 widely spreading or the lower reflexed, obscurely triangular, nerveless, membran- 

 aceous, long-beaked, the beak obliquely cut, becoming bidentulate. Achenes 

 usually triangular. Stigmas 3, or occasionally 2. 



3. C. pyrenaica Wahl. Culms 3-20 cm. high, wiry, slender, smooth; leaves 

 2-3 to a fertile culm; spike 5-20 mm. long, 3-5 mm. wide; scales chestnut tinged; 

 perigj^nia 3-4 mm. long. Alpine localities: Mack. — Colo. — Ore. — Alaska; 

 Eurasia. Alp. — Subalp. Jl-S. 



4. C. nigricans C. A. Meyer. Culms 5-20 cm. high, stiff, firm, smooth; 

 leaves 4-9 to a fertile culm; spike 8-15 mm. long, 6-9 mm. wide; scales dark 

 brown tinged; perigj-nia 4 mm. long. Alpine localities: Alta. — Colo. — Calif. — • 

 Alaska. Alp. — Mont. Jl-S. 



4. Capitatae Christ. Cespitose, the rootstocks somewhat elongate. Leaf- 

 blades filiform. Spike soUtary, ovoid, androg^Tious, densely flowered, bractless. 

 Perigynia plano-convex, sharp-edged, not inflated, the walls thinnish, essentially 

 nerveless, sessile, the smooth beak conspicuously hyaline-tipped, in age bidentu- 

 late. Achenes lenticular. Stigmas 2. 



5. C. capitata L. Culms 1-2 dm. high; leaf-blades about 0.5 mm. wide; 

 spike with 6-25 ascending perigynia; scales ovate-orbicular, obtuse; perigynia 

 2-2.5 mm. long, and about as broad, abruptly beaked. An arctic species also 

 occurring very locally on mountain summits southward: Greenl. — Alaska; also 

 N.H.; Alta.; Calif.; Nev.; Mex.; Eu. Alp. Je-Au. 



5. DioiCAE Tuckerm. Rootstocks elongate. Culms slender. Leaf-blades 

 filiform. Spike solitary, bractless, staminate, pistillate or androgjTious, narrow. 

 Perigynia at length widely spreading, piano- or bi-convex, not inflated, subcori- 

 aceous, glabrous, nerved, rounded and spongy at base, sharp-edged, strongly 

 beaked, the apex hyaline, in age bidenticulate. Achenes lenticular. Stigmas 2. 



6. C. gynocrates Wormskj. Culms 1-3 cm. high, smooth; rootstocks 

 horizontal; spike 5-15 mm. long, 2-5 mm. wide; scales sharp-pointed, reddish 

 brown; perigynia few, 3 mm. long, biconvex, nerved, narrowed into a rough 

 beak half as long as the body. Sphagnum swamps: Greenl.- — -N.Y. — Mich. — 

 Colo. — -Alaska; Siberia-. Alp. — Mont. Southward local. My-Au. 



6. FoETiDAE Tuckerm. Rootstocks elongate, dark-colored, the culms arising 

 singly or a few together. Leaf-blades narrow. Spikes few to several, androgy- 

 nous, aggregated into a dense siibglobose or ovoid head. Perigynia spreading, 

 plano-convex, membranaceous, usually obsoletely nerved, loosely enveloping 

 the achene, rounded at the base, stipitate, the beak obliquely cut, at times 

 bidentulate. Achenes lenticular. Stigmas 2. 



7. C. vernacula Bailey. Culms 1-2 dm. high, smooth; leaf-blades 5-12 

 cm. long, stiff; head very dense, globose, about 1 cm. in diameter; perigynia 

 ovoid, 3.5-4 mm. long, 1.5 mm. wide, scarcely inflated, more or less nerved. 

 Alpine slopes: Wyo.- -Colo. — Calif. — Wash. Alp. Jl-Au. 



8. C. perglobosa Mackenzie. Culms 1-1.5 dm. high, smooth; leaf-blades 

 2-8 cm. long; head very dense, globose, about 1 cm. in diameter; perig>Tiia 

 ovoid-elliptic, 4 mm. long, 2.25 mm. wide, membranous, not stipitate, more or 

 less inflated. C. incurva Liglitf. var. chartacea Kukenth. Alpine ridges: Colo. 

 Alp. Au-S. 



9. C. incurviformis Mackenzie. Culms 2-5 cm. high, smooth, obtusely 

 angled; leaf-blades 2-4 cm. long; head dense, globose, 7-9 mm. in diameter; 

 scales lance-ovate, chestnut with narrow hyaline margins, acuminate; perigynia 



