Rhynchospora nitens (Vahl) A. Gray
Family: Cyperaceae
Rhynchospora nitens image
Paul Rothrock  
Plants annual, cespitose or solitary, (10-)20-100 cm; rhizomes absent. Culms erect, leafy, nearly terete or angled, many ribbed. Principal midculm leaves often exceeding inflorescences; blades linear, proximally flattened, 1-5 mm wide, apex trigonous, tapering. Inflorescences terminal and axillary, clusters of corymbs 1-5, usually diffuse; leafy bracts exceeding proximal corymbs. Spikelets dark brown, lanceoloid to ovoid, mostly 4-6(-8) mm, apex acute; fertile scales many, ovate, rounded-convex, 2-3.5 mm, apex acute, midrib mostly included, rarely forming apiculus. Flowers: perianth absent. Fruits 1-1.3(-1.5) mm, body dark brown, tumidly lenticular, nearly orbicular, 0.7-1 × 0.7-1 mm, margins strong, interrupted at tubercle base; surfaces irregularly transversely rugulose with wavy rows of vertical, linear, raised cells; tubercle depressed-triangular, 0.1-0.3 mm, capping fruit summit, base broadly 2 lobed. Fruiting summer-fall or all year. Moist to wet sands or peats of stream banks, pond shores, depressions in savannas, marshes; 0-100 m; Ala., Del., Fla., Ga., Ind., La., Mass., Mich., Miss., N.J., N.Y., N.C., S.C., Tex., Va.; West Indies; Central America.
Annual herb, tufted or solitary 20 cm - 1 m tall Leaves: alternate, three-ranked, 1 - 5 mm wide, flat basally, linear with a tapering and three-sided tip, parallel-veined, with a sheathing base that encloses the stem. Sheaths opening at the top. Inflorescence: a loosely clustered group of one to five spikelet clusters, terminal and axillary, subtended by leaf-like bracts. Spikelet clusters cylindrical to egg-shaped. Flowers: minute, subtended by a floral scale, lacking sepals and petals. Stamens one or two, exserted. Pistil one. Style two-cleft. Fruit: a one-seeded achene, scarcely stalked, dark brown, to 1 mm long (not including tubercle) and 1 mm wide, more or less round, biconvex, wrinkled. Tubercle tiny, flattened, triangular with a broadly two-lobed base, appressed. Culm: upright, 20 cm - 1 m long, nearly circular in cross-section or angled, ribbed, solid, leafy. Spikelets: dark brown, 4 - 6 mm long, lance-shaped to egg-shaped with a pointed apex. Floral scales spirally arranged and overlapping, 2 - 3.5 mm long, egg-shaped with a pointed apex, one-ribbed, thin.

Similar species: No information at this time.

Habitat and ecology: Known only from Porter County, Indiana and likely extirpated in the Chicago Region. Found in wet sandy soil.

Occurence in the Chicago region: native

Etymology: Rhynchospora comes from the Greek words rhynchus, meaning beak, and spora, meaning seed, referring to the beaked achene. Nitens means shining.

Author: The Morton Arboretum

From Flora of Indiana (1940) by Charles C. Deam
In sandy soil on the borders of sloughs. My only specimen is one collected by Umbach on the border of a slough at Dune Park, Porter County, in 1899. Evidently it is very local.


Indiana Coefficient of Conservatism: C = 10

Wetland Indicator Status: OBL

Much like no. 1 [Rhynchospora scirpoides (Torr.) Griseb.]; achene scarcely stipitate, transversely conspicuously rugose, only inconspicuously margined; tubercle very short and closely appressed. Wet sandy soil and bogs; se. Mass. to Tex.; nw. Ind. (Psilocarya n.)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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