26n. CAREX Linnaeus sect. DEWEYANAE (Tuckerman ex Mackenzie) Mackenzie in N. L. Britton et al., N. Amer. Fl. 18: 114. 1931.
Robert F. C. Naczi
Carex [unranked] Deweyanae Mackenzie in N. L. Britton and A. Brown, Ill. Fl. N. U.S. ed. 2, 1: 352. 1913
Plants densely to loosely cespitose, short to long rhizomatous. Culms brown at base. Leaves: basal sheaths fibrous; sheath fronts membranous; blades flat or V-shaped in cross section when young, glabrous. Inflorescences racemose with (2–)3–9 spikes; proximal bracts filiform or leaflike, sheathless; lateral spikes gynecandrous or pistillate, rarely staminate or androgynous, sessile, without prophylls; terminal spike usually gynecandrous. Proximal pistillate scales whitish to castaneous, hyaline margins and green, 1-veined center, apex acute or short-awned. Perigynia appressed-erect to spreading, occasionally recurved, veined or veinless on both faces, sessile, ovate to narrowly lanceolate, plano-convex, base cuneate to rounded, with spongy tissue, margins acutely angled, serrulate or entire distally, apex tapering or abruptly beaked, glabrous; beak 0.4–2.5(–2.8) mm, with abaxial suture usually nearly closed, margins entire or serrulate, apex entire to shortly bidentate. Stigmas 2. Achenes brown, sessile, biconvex or plano-convex, almost as large as bodies of perigynia, apex rounded; style deciduous, enlarged at base.
Species 8 (6 in the flora): North America, e Asia.
Species of Carex sect. Deweyanae, particularly C. bolanderi, C. deweyana, and C. leptopoda, can be difficult to identify because of their great morphologic variability and overlapping ranges of measurements of diagnostic characters. For correct identifications, specimens must bear mature perigynia, be complete, and be ample. Perigynia from the middle portions of spikes should be examined because they are the most representative. Perigynium beak length reported here is the distance from the achene summit (as viewed through the perigynium) to the perigynium apex. Culm widths are taken from the middle of the culm.