Eleocharis melanocarpa |
Eleocharis occulta |
|
---|---|---|
black-fruit spike-rush, black-fruit spikesedge |
limestone spike-rush |
|
Habit | Plants perennial, densely cespitose; rhizomes concealed by persistent dead culm bases, often ascending, short, 3–5 mm thick, hard, cortex persistent, internodes very short, scales decaying to coarse fibers, 5–12 mm, papery. | |
Culms | 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. |
subterete to slightly compressed, less than 2 times wider than thick, with 4–7 blunt ridges when dry, 27–56 cm × 0.2–0.5(–0.7) mm, firm to hard, spongy. |
Leaves | distal leaf sheaths brown to reddish. |
distal leaf sheaths persistent, not splitting, proximally red, distally green to stramineous, often inflated, thinly papery to membranous, sometimes translucent, apex broadly obtuse to subtruncate, often callose, tooth absent. |
Spikelets | 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, 3–10 × 2–3 mm, apex acute; proximal scale amplexicaulous, apex 2-fid; subproximal scale with a flower; floral scales spreading in fruit, 20–50, 7 per mm of rachilla, medium brown, midrib region often narrowly stramineous, carinate, lanceolate-attenuate, 2–2.8 × 1 mm, apex 2-fid. |
Flowers | perianth bristles present, sometimes rudimentary, brown, length variable, obscurely retrorsely spinulose; anthers brown, 1.7–2.2 mm. |
perianth bristles 3 or absent, stramineous to pale brown, rudimentary to 1/2 achene length, obscurely retrorsely spinulose; stamens 3; anthers orange-brown, 0.7–1.3 mm; styles 3-fid. |
Achenes | subdeltoid in outline, sometimes broadly obpyriform, equilaterally trigonous, angles prominent, 0.9–1.2 × 0.7–1.1 mm, apex truncate. |
falling with scales, medium or dark brown, obpyriform, nearly equilaterally obscurely trigonous or cross section nearly circular, 0.7–1 × 0.5–0.65 mm, neck distinct or rarely absent, obscurely rugulose at 10–30X, 30 or more low, blunt horizontal ridges in vertical series. |
Tubercles | sessile, depressed-pyramidal, often apiculate, as wide as achene, 0.3–0.5 × 0.7–1.1 mm. |
brown, depressed-pyramidal, often rudimentary, 0.1–0.15 × 0.2 mm. |
Eleocharis melanocarpa |
Eleocharis occulta |
|
Phenology | Fruiting summer. | Fruiting spring (Mar–May), sometimes summer (Jul). |
Habitat | Fresh, oligotrophic, acid, sandy or peaty, often drying shores, ponds, ditches | Seasonally wet, calcareous seeps, depressions, swales, rock crevises, rocky stream beds, stream banks, wet meadows, pond margins, often on limestone |
Elevation | 10–300 m (0–1000 ft) | 80–300 m (300–1000 ft) |
Distribution |
AL; FL; GA; IN; MA; MI; NC; NY; RI; SC; TX; VA
|
OK; TX |
Discussion | Eleocharis melanocarpa is reported from Rhode Island; I have not seen a voucher specimen. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eleocharis occulta is very invariable in contrast to the extreme variability of E. compressa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 89. | FNA vol. 23, p. 83. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Melanocarpae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis |
Sibling taxa | ||
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 3: 311. (1836) | S. G. Smith: Novon 11: 247, figs. 2, 3E–K. (2001) |
Web links |