Eleocharis microcarpa
Ann. Lyceum Nat. Hist. New York 3: 312. 1836.
Plants usually annual, tufted, sometimes mat-forming via proliferating and arching inflorescences (stoloniferous), sometimes entirely vegetative; rhizomes absent. Culms often ascending or arching, quadrangular or broadly elliptic, 2–40 cm × 0.1–0.4 (–0.6) mm, soft. Leaves: distal leaf-sheaths persistent or disintegrating, pale-brown, green or redbrown, streaked or mottled-redbrown or purple, translucent, membranous, apex narrowly acute. Spikelets: basal spikelets absent; often proliferous, ovoid to ellipsoid or lanceoloid, terete, 2–10.7 × 1–2 mm, apex acute; proximal scale empty, persistent, amplexicaulous, dissimilar to floral scales, often longer, often resembling an involucral-bract, ovate to lanceolate, midrib markedly thickened and broad and often prolonged beyond lamina; subproximal scale with flower; floral scales spiraled, colorless, whitish, or pale-brown, streaked or mottled-redbrown or purple, midribs green and redbrown or green and purple, ovate to elliptic, 0.8–1.5 × 0.4–0.8 mm, membranous, midrib obscure to prominent. Flowers: perianth bristles present or sometimes apparently absent; stamens 3; anthers 0.15–0.35; styles 3-fid. Achenes whitish to olive or pale-brown, sometimes spotted olive or redbrown, obovoid, trigonous (or subterete), angles prominent, 0.55–0.8 × 0.3–0.5 mm, apex constricted proximal to tubercle, smooth. Tubercles green or pale-brown to redbrown, trigonous.
Distribution
Ala., Fla., Ga., Ind., La., Mass., Md., Mich., Miss., N.C., N.J., Pa., S.C., Tenn., Tex., Va., West Indies
Discussion
Varieties 2 (2 in the flora).
Specimens of Eleocharis brittonii and E. microcarpa without achenes are often difficult to distinguish. More detailed study of the four apparent entities across the two species is warranted.
Selected References
None.
Key
| 1 | Perianth bristles 0.2–0.4 mm, shorter than achene; proximal scale of spikelets 0.4–0.5 mm wide. | Eleocharis microcarpa var. microcarpa |
| 1 | Perianth bristles 0.6–1 mm, shorter than to equaling achene; proximal scale of spikelets 0.8–1 mm wide. | Eleocharis microcarpa var. filiculmis |
"shortened" is not a number.