Eleocharis melanocarpa |
Eleocharis bicolor |
|
---|---|---|
black-fruit spike-rush, black-fruit spikesedge |
two-tone spikerush |
|
Habit | Plants probably perennial, tufted, not stoloniferous; rhizomes present, ± horizontal, 0.2–0.4 mm thick, firm, longer internodes 3–7 mm, scales translucent or not. | |
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. |
often ascending, often spotted or streaked red-brown, cross section quadrangular or broadly elliptic, often sulcate, 1.5–8(–25) cm × 0.1–0.3 mm, soft. |
Leaves | distal leaf sheaths brown to reddish. |
distal leaf sheaths persistent or fugaceous, closely sheathing, not conspicuously wrinkled, colorless or pale brown, sometimes spotted red-brown, delicately membranous, apex narrowly acute. |
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. |
basal spikelets absent; never proliferous, ovoid or ellipsoid, laterally compressed or terete, 1.5–3.7 × 0.8–3 mm, apex acute; proximal scale empty, persistent, amplexicaulous, similar to floral scales; subproximal scale with a flower; floral scales distichous (spirodistichous), 8–22, 6–10 per mm of rachilla, colorless or pale brown, mottled red-brown to purple, ovate, (1–)2 × 1 mm, membranous, midribs green and red-brown, prominent, apex rounded to obtuse. |
Flowers | perianth bristles present, sometimes rudimentary, brown, length variable, obscurely retrorsely spinulose; anthers brown, 1.7–2.2 mm. |
perianth bristles present or absent, (1–)4, colorless to white, vestigial to shorter than achene, 0–0.55 mm; spinules not evident at 45X; stamens (1–)3; anthers 0.35–0.45 mm; styles 2-fid (or 3-fid). |
Achenes | subdeltoid in outline, sometimes broadly obpyriform, equilaterally trigonous, angles prominent, 0.9–1.2 × 0.7–1.1 mm, apex truncate. |
whitish to pale brown, obovoid, biconvex, rarely trigonous, angles prominent, 0.5–0.8 × 0.4–0.6 mm, apex slightly constricted proximal to tubercle, smooth. |
Tubercles | sessile, depressed-pyramidal, often apiculate, as wide as achene, 0.3–0.5 × 0.7–1.1 mm. |
sessile, green or red-brown, pyramidal, birettaform or umbonate, 0.15–0.25 × 0.3–0.4 mm. |
Eleocharis melanocarpa |
Eleocharis bicolor |
|
Phenology | Fruiting summer. | Fruiting summer–late fall. |
Habitat | Fresh, oligotrophic, acid, sandy or peaty, often drying shores, ponds, ditches | Moist banks, freshwater, damp pine barrens |
Elevation | 10–300 m (0–1000 ft) | 0–50 m (0–200 ft) |
Distribution |
AL; FL; GA; IN; MA; MI; NC; NY; RI; SC; TX; VA
|
FL; GA; MS; West Indies; Central America (Nicaragua) |
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.) |
Of conservation concern. The culms of Eleocharis bicolor sometimes have complete transverse septa which are prominent when plants are aquatic. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 89. | FNA vol. 23, p. 96. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Melanocarpae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 3: 311. (1836) | Chapman: Fl. South. U.S., 517. (1860) |
Web links |