Eleocharis microcarpa

Torrey

Ann. Lyceum Nat. Hist. New York 3: 312. 1836.

Illustrated
Treatment appears in FNA Volume 23. Treatment on page 95. Mentioned on page 94.

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

V23 134-distribution-map.jpg

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.

... more about "Eleocharis microcarpa"
with longitudinal rows +, smooth +  and honeycomb-reticulate +
redbrown +, spotted olive +, whitish +  and olive or pale-brown +
smooth +  and markedly sculptured +
trigonous;obovoid +
0.055 cm0.55 mm <br />5.5e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
0.3mm;0.5mm +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
acute;acute +
constricted +
Jeremy J. Bruhl +  and S. Galen Smith +
Torrey +
flattened +
0 cm0 mm <br />0 m <br /> (6 cm60 mm <br />0.06 m <br />) +
persistent +
enlarged +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
parallel +  and divergent +
terete +, rolled +  and plicate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
2 cm20 mm <br />0.02 m <br /> (40 cm400 mm <br />0.4 m <br />) +
arching +  and ascending +
elliptic +  and quadrangular +
0.1mm;0.4mm +
purple +, mottled-redbrown +, streaked +, redbrown +, green +  and pale-brown +
Ala. +, Fla. +, Ga. +, Ind. +, La. +, Mass. +, Md. +, Mich. +, Miss. +, N.C. +, N.J. +, Pa. +, S.C. +, Tenn. +, Tex. +, Va. +  and West Indies +
purple +, mottled-redbrown +, streaked +, pale-brown +, whitish +  and colorless +
papery +  and membranous +
hypogynous +  and subtending +
biconvex +  and trigonous +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
green and redbrown or green and purple +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
obscure +  and prominent +
ovate +  and elliptic +
membranous +
0.4mm;0.8mm +
flattened +
0 cm0 mm <br />0 m <br /> (6 cm60 mm <br />0.06 m <br />) +
with (1-)3-6(-30) bristles and/or scales +
2-3(-4)-carpellate +
3 (?) +  and 1 (?) +
amplexicaulous +  and empty +
stramineous;medium brown or red brown or blackish brown +
ovate +  and lanceolate +
Ann. Lyceum Nat. Hist. New York +
ascending +  and creeping +
caudex-like +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
adventitious +
basal +  and proximal +
2-keeled +
cylindric +
Illustrated +
stoloniferous +
proliferating +
0.2 cm2 mm <br />0.002 m <br /> (1.07 cm10.7 mm <br />0.0107 m <br />) +
terete;ovoid;ellipsoid or lanceoloid +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
Eleocharis +
Eleocharis microcarpa +
Eleocharis (sect. Eleocharis) ser. Tenuissimae +
species +
pale-brown;redbrown +
trigonous +
plant +  and mat-forming +