Rhynchospora capitellata

(Michaux) Vahl

Enum. Pl. 2: 235. 1805.

Common names: Rhynchospore à petites têtes
Basionym: Schoenus capitellatus Michaux Fl. Bor.-Amer. 1: 36. 1803
Synonyms: Phaeocephalum glomeratum var. minus (Britton) Farwell Rhynchospora capitellata var. leptocarpa (Chapman ex Britton) S. F. Blake Rhynchospora capitellata var. minor (Britton) S. F. Blake Rhynchospora glomerata var. minor Britton Rhynchospora leptocarpa
Treatment appears in FNA Volume 23. Treatment on page 210. Mentioned on page 202, 211, 214.
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Plants perennial, cespitose, 20–100 cm; rhizomes absent. Culms arching-ascending, leafy, obtusely trigonous, slender; principal leaves overtopped by inflorescence; blades flat, to 3 mm, apex tapering, trigonous. Inflorescences terminal and axillary, clusters 1–5 or more, compact, turbinate or hemispheric, 1–1.5 cm wide; peduncles progressively shorter distally on culm; bracteal leaves mostly exceeding subtended compounds. Spikelets rich deep brown, rarely pale brown, lanceellipsoid, 3.5–4(–5) mm; fertile scale elliptic, 2.7–3 mm, apex acute or rounded, midrib shortexcurrent or not. Flowers: perianth absent. Fruits (1–)2–3(–5) per spikelet, (2–)2.5–3 mm; body redbrown with pale central disc, stipitate, lenticular, obovoid, 1.2–1.5 × 0.7–1(–1.2) mm, margins pale, wirelike, surfaces slick; tubercle triangular-subulate, (0.8–)1–1.2(–1.6) mm.

Phenology: Fruiting summer–fall.
Habitat: Moist to wet meadows, swales, seeps, stream banks, flatwoods, fens, and bogs
Elevation: 0–1600 m


V23 361-distribution-map.jpg

N.B., N.S., Ont., Que., Ala., Ark., Calif., Conn., Del., D.C., Fla., Ga., Ill., Ind., Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis.


Rhynchospora capitellata occurs infrequently in the lower Gulf coastal plain (in Florida, only north) and intergrades with R. glomerata. Forms with antrorsely barbellate bristles are referred to forma controversa (S. F. Blake) Gale; those with smooth bristles are named forma discutiens (C. B. Clarke) Gale (S. Gale 1944). Occasional forms with trigonous fruits occur.

Bruce Sorrie (pers. comm.) believes that many of the southern coastal plain records for Rhynchospora capitellata are based on examples of a neglected taxon, R. leptocarpa (Chapman) Small (J. K. Small 1933), and he wishes to reinstate it. Occurring in semi-shady moist sites in steepheads, or from seeps and shallows along blackwater streams, the plants are mostly distinguished by the tall, lax habit; the many distant, small clusters of light brown or tan spikelets; and the softer, more lax foliage. Measures of spikelets, fertile scales, perianth, achenes, and fruit tubercles show a strong overlap with those of southern examples of R. capitellata. The long, lax culm habit, the softer and paler foliage, and the paler spikelets could well be ecologic responses, or the plants could indeed represent a geographic variant.

Selected References


Lower Taxa

... more about "Rhynchospora capitellata"
Robert Kral +
(Michaux) Vahl +
Schoenus capitellatus +
Rhynchospore à petites têtes +
N.B. +, N.S. +, Ont. +, Que. +, Ala. +, Ark. +, Calif. +, Conn. +, Del. +, D.C. +, Fla. +, Ga. +, Ill. +, Ind. +, Kans. +, Ky. +, La. +, Maine +, Md. +, Mass. +, Mich. +, Minn. +, Miss. +, Mo. +, N.H. +, N.J. +, N.Y. +, N.C. +, Ohio +, Oreg. +, Pa. +, R.I. +, S.C. +, Tenn. +, Tex. +, Vt. +, Va. +, W.Va. +  and Wis. +
0–1600 m +
Moist to wet meadows, swales, seeps, stream banks, flatwoods, fens, and bogs +
Fruiting summer–fall. +
Illustrated +  and Endemic +
Phaeocephalum glomeratum var. minus +, Rhynchospora capitellata var. leptocarpa +, Rhynchospora capitellata var. minor +, Rhynchospora glomerata var. minor +  and Rhynchospora leptocarpa +
Rhynchospora capitellata +
Rhynchospora +
species +