Siberian Bog Sedge

Kobresia macrocarpa Clokey, sp. no v
Very densely cespitose, in large to small clumps, not stoloniferous, the rootstocks very short, not at all creeping, tough, thick, lignescent, the culms 0.3-1 dm. high, stiff, strict, stoutish, wiry, obtusely triangular, smooth, exceeded by the leaves, phyllopodic, dull-cinnamonbrown-tinged at base, the persistent dried-up leaves of the previous year conspicuous, mostly reduced to bladeless sheaths; leaves with well-developed blades 7-15 to a culm, densely clustered on lower fifth or sixth, the blades acicular, dull-green, 0.2-1.5 dm. long, 0.25-0.5 mm. wide, erect to strongly curved, long-attenuate, roughened towards apex, the tips usually dried-up, tapering into the strongly striate, chartaceous, very conspicuous, smooth, somewhat shining, cinnamon-brown sheaths, sparingly fibrillose in age, hyaline and somewhat reddishbrown-tinged and concave at mouth ventrally, the ligule about as long as wide; spike solitary, bractless, linear-oblong, often somewhat clavate, 1-2 cm. long, 4—5 mm. wide, closely 8-15flowered, the terminal flowers staminate, the lateral pistillate; scales broadly obovate, 4—5 mm. long, obtuse, persistent, closely appressed, rounded on back, dull-brown with midvein conspicuous below only, not extending to tip, the upper margins conspicuously whitishhyaline and scarious, entirely concealing the perig>'nia; perigynia narrowly oblong-elliptic, 5.5 mm. long, 1.25 mm. wide, membranaceous, smooth, shining, whitish below, yellowishbrown above, finely many-nerved, sessile, tapering at base, hyaline at apex, the margins united towards lower part; achenes shorter than perigynia, narrowly oblong-obovoid, 3.5 mm. long, 1 mm. wide, greenish, soon dull-brown, triangular, with sides slightly concave below, the angles rounded and not conspicuous, broadly short-stipitate, tapering into the short greenish beak, obscurely jointed with the straight, slender, brownish style; stigmas three, long, slender, brown, reflcxed; rachilla present, slender, whitish, about equaling achene.
Type collected in fairly moist soil among rocks. Pike's Peak. El Paso County, Colorado, alt. 3590 m., August 30. 1920, Clvkcy 3651 (herb. N. Y. Bot. Gard.).
Distribution: Fairly moist, calcareous soil, summits of high peaks, central Colorado. (Specimens examined from central Colorado only.)

Kobresia sibirica, the Siberian bog sedge, is a plant species known from arctic and alpine tundra in Siberia, the Russian Far East, Alaska, Yukon, the Canadian Northwest Territories, Nunavut, British Columbia, Colorado (several counties in the Rockies), Utah (Duchesne County), Montana (Carbon County), and Wyoming (Park County). Some authorities have considered the North American collections as distinct species (K. macrocarpa, described from Colorado, and K. hyperborea from the Canadian Arctic), but they are more often tentatively regarded as conspecific with K. siberica, but this is pending further investigation.

Kobresia sibirica is a perennial herb spreading by means of underground rhizomes. Culms are up to 40 cm tall. Leaves are narrow and thread-like, up to 15 cm long. Lower spikelets generally have both pistillate and staminate flowers, while uppermost spikelets are staminate only.