Eleocharis melanocarpa
Eleocharis brachycarpa
black-fruit spike-rush, black-fruit spikesedge
shortfruit spikerush
to 2 times wider than thick, 35–60(–70) cm × 0.5–1.3 mm, hard, usually with to 10 blunt ribs, at 20X often finely ridged and minutely granular.
mostly ascending, 4-angled, sulcate, 5 cm × 0.1–0.2 mm, soft.
distal leaf sheaths brown to reddish.
distal leaf sheaths persistent, colorless, translucent, apex narrowly acute.
3–12 × 3–4 mm;
proximal scale amplexicaulous, 3.5–4 mm, midrib region very broad and fleshy, apex entire;
subproximal scale with a flower;
floral scales 30–40, 8–10 per mm of rachilla, orange-brown to stramineous, midrib region stramineous, broadly ovate, papery or sometimes membranous, 3–4 × 2 mm, apex entire, rounded.
ovoid, 2–3 × 1–2 mm, apex blunt;
floral scales 10–30, ca. 10 per mm of rachilla, orange-brown to stramineous with broad colorless margin, midrib region stramineous, lanceolate, folded lengthwise, 1.5–2 × 0.8–1 mm, midrib prominent, apex acuminate.
perianth bristles present, sometimes rudimentary, brown, length variable, obscurely retrorsely spinulose;
anthers brown, 1.7–2.2 mm.
perianth bristles absent;
anthers 0.7–1.2 mm.
subdeltoid in outline, sometimes broadly obpyriform, equilaterally trigonous, angles prominent, 0.9–1.2 × 0.7–1.1 mm, apex truncate.
whitish, broadly obpyriform, much less than 2 times longer than wide, angles and longitudinal ridges ca. 6, obscure, 0.4 × 0.3 mm, apex blunt, trabeculae 20, indistinct, crowded.
sessile, depressed-pyramidal, often apiculate, as wide as achene, 0.3–0.5 × 0.7–1.1 mm.
brownish, not appressed, mostly pyramidal, 0.1 × 0.1 mm.
Eleocharis melanocarpa
Eleocharis brachycarpa
Eleocharis melanocarpa is reported from Rhode Island; I have not seen a voucher specimen.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Eleocharis brachycarpa is unique among the North American members of subg. Scirpidium in its floral scales, which are markedly spreading in fruit, often apparently decussate when pressed, narrowly lanceolate, and folded lengthwise so that they do not press open and flat. It is apparently very rare and local. It is admitted to the flora only on the basis of labels on a paratype (Berlandier 996) and on Berlandier 2426, both of which read “In locis paludosis – De Matamoros a las Nueces [River, Texas], Ap. 1834.” H. K. Svenson (1929) mistranscribed the locality “Nueces,” publishing it as “Mueres.” We have also seen a specimen from Mexico, Tamaulipas, 24 mi. N of San Fernando, edges of resacas, elev. 15 m, 1959, M.C. Johnston 4882C (TEX).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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