26hh. CAREX Linnaeus sect. AULOCYSTIS Dumortier, Fl. Belg. 147. 1827.
Peter W. Ball & Joy Mastrogiuseppe
Carex sect. Ferrugineae (Tuckerman) Kükenthal
Plants cespitose, short to long rhizomatous, sometimes stoloniferous. Culms brown at base, shorter than leaves. Leaves: basal sheaths not fibrous; sheath fronts membranous; blades V-shaped in cross section when young, proximal leaf blades with lateral veins equally prominent, distal leaf blades at least 2 mm, glabrous. Inflorescences racemose, with 2–8+ spikes; proximal nonbasal bracts filiform or scalelike, sheathing at least 3 mm, longer than diameter of stem; lateral spikes pistillate, androgynous, or, rarely, staminate, pedunculate, prophyllate, pistillate scales ovoid, with not more than 25 perigynia; terminal spike staminate, androgynous, or gynecandrous. Proximal pistillate scales dark brown to almost black, 1–3-veined, apex obtuse to acuminate. Perigynia ascending or spreading, purplish black at least distally, or black-mottled, veinless or weakly veined, sometimes with 2, strong, marginal veins, stipitate, lanceolate to ovate, biconvex or trigonous in cross section, less than 10 mm, base tapered to rounded, apex tapering or abruptly beaked, glabrous, setose, or hispidulous; beak straight, ± bidentate. Stigmas (2–)3. Achenes trigonous, rarely biconvex, smaller than bodies of perigynia; style deciduous.
Species probably over 50 (8 in the flora): temperate and artic regions of North America and Eurasia, primarily in temperate Asia.
Ball, P. W. and M. Zoladz. 1994. The taxonomy of Carex petricosa (Cyperaceae) and related species in North America. Rhodora 96: 295–310. Dietrich, W. 1967. Die Cytotaxonomie der Carex-Sektion Frigidae in Europa. Feddes Repert. 75: 1–40.