Carex diandra - (image 1 of 6)
Taxonomy
Family: Cyperaceae
Section Heleoglochin
Section Heleoglochin forms a natural group with sections Multiflorae and Vulpinae, all of which have very short, slender, tough, dark brown to blackish rhizomes, sheath fronts dotted red or copper, and relatively short anthers (1-2.5 mm).
Habitat
Swamps, wet meadows, sphagnum bogs.
Associates
Distribution
Circumboreal, south in North America to NJ, PA, IN, MO, CO, and CA.
Morphology
Stems clustered, 30-100 cm, aphyllopodic, elongate and rather slender above; leaves elongate, mostly flat, typically 1-2.5 mm wide; sheaths ventrally pale and red-dotted, prolonged 2-3 mm beyond the base of the blade; spikes androgynous, small, sessile, aggregated into a compact but branched inflorescence 2-3.5(-5) cm long and mostly less than 1 cm thick; bracts small, setaceous or similar to the pistillate scales; stamens 3; scales mostly hyaline-scarious and stramineous or brownish, with a firm, sometimes shortly excurrent midrib; perigynia ovate to lance-ovate, 2.4-3 mm long and half as wide, usually dark brown, shining, somewhat spreading, very firm and thick-walled, the ventral surface nerveless, slightly convex, and often exposed in the spike, the dorsal surface strongly convex with a thin, often depressed pale median strip bordered by a pair of veins; body more or less abruptly contracted to the beak; beak coarse, serrulate-margined, often pale or greenish; achene lenticular.
Notes
Fruiting late May to mid August
Wetland indicator: OBL
Similar to C. prairea which lacks the thin, often depressed pale median strip on the dorsal surface of the perigynium and has the ventral side of the sheaths strongly copper-red towards the apex. In C. diandra the apex of the sheath is merely red-dotted.
References
Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of
Northeastern United States and Adjacent Canada. Second Ed.
The New York Botanical Garden. Bronx, NY
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© Michael Hough 2018 |