Carex sect. Clandestinae
in J. C. Loudon, Hort. Brit., 376. 1830.
Plants cespitose, short to long rhizomatous. Culms red-purple at the base, shorter or longer than leaves. Leaves: basal sheaths not fibrous; sheath fronts membranous; blades V-shaped in cross section when young, glabrous, widest leaf blades 2–4 mm wide, distal leaves bladeless or with blades 1 mm or less, not longer than sheaths. Inflorescences racemose, with 2–6 spikes; proximal nonbasal bracts bladeless or blade usually less than 2 mm, purple tinged, sheathing; lateral spikes pistillate or androgynous, with not more than 25 perigynia, sometimes basal, pedunculate, prophyllate, ovoid; terminal spike staminate or androgynous. Proximal pistillate scales dark brown to black, apex obtuse to subacute, cuspidate or awned. Perigynia erect or ascending, veinless or veined with 2 prominent marginal veins, stipitate, obovoid, rounded-trigonous, 2–3.5 mm, base tapering or cuneate, apex abruptly contracted to beak, pubescent, sometimes glabrescent; beak straight or bent, 0.2–0.5 mm, orifice entire or emarginate. Stigmas 3–4. Achenes trigonous, rarely quadrangular, almost as large as bodies of perigynia; style deciduous.
Circumboreal (circumpolar and north temperate).
Species ca. 20 (4 in the flora).
Carex sect. Clandestinae has close affinities with sect. Pictae Kükenthal and perhaps with sect. Acrocystis Dumortier. The Eurasian species, C. ericetorum Pollich, which has been placed in sect. Acrocystis by Eurasian authors, actually belongs in sect. Clandestinae, based on its bract morphology and perigynium pubescence. Although most species of sect. Clandestinae, as circumscribed here, form a cohesive morphologic group, C. pedunculata shows a number of similarities to C. baltzellii Chapman of sect. Pictae, including inflorescence morphology, scale morphology, and perigynium pubescence. Developmental and anatomic studies may help to determine whether the sections with pubescent perigynia exhibit homologous or analogous character states.
|1||Most pistillate spikes emerging from basal nodes on long peduncles to 13 cm; pistillate scales retuse to obtuse, cuspidate; perigynia 3.7–6 mm; leaves dark green, equaling or mostly exceeding culms.||Carex pedunculata|
|1||All pistillate spikes emerging from cauline nodes on shorter peduncles or sessile; pistillate scales acute to obtuse; perigynia less than 3.5 mm; leaves pale green, shorter than culms.||> 2|
|2||Staminate spikes less than 7 mm; anthers less than 2 mm; plants densely cespitose, short-rhizomatous.||Carex concinna|
|2||Staminate spikes usually more than 10 mm; anthers more than 2 mm; plants loosely cespitose, long-rhizomatous.||> 3|
|3||Stigmas 3, flexuous, thin, strongly papillose; pistillate spikes widely separated, proximal spikes long-pedunculate, peduncles to 7 cm; proximal bracts long-sheathing; transcontinental.||Carex richardsonii|
|3||Stigmas 4, erect or convolute, thick, weakly papillose; pistillate spikes aggregated, subsessile or short-pedunclulate; proximal bracts short-sheathing; northwestern.||Carex concinnoides|