Eleocharis melanocarpa |
Eleocharis bolanderi |
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black-fruit spike-rush, black-fruit spikesedge |
Bolander's spikerush |
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Habit | Plants perennial, densely tufted; rhizomes caudexlike, mostly hidden by culms and roots, short, 1.5–3 mm thick, hard, cortex persistent, internodes very short, scales not evident. | |
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, often with to 6 prominent ridges when dry, sulcate, 10–30 cm × 0.3–0.5 mm, firm to rigid, spongy. |
Leaves | distal leaf sheaths brown to reddish. |
distal leaf sheaths persistent, not splitting, proximally brown, red, or stramineous, distally stramineous, green or reddish, papery, apex sometimes reddish, obtuse, rarely 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, 3–8 × 2–3 mm, apex acute to obtuse; proximal scale amplexicaulous, entire; subproximal scale with flower; floral scales spreading in fruit, 8–30, 4–5 per mm of rachilla, dark brown to blackish, midrib regions often stramineous or greenish, ovate to lanceolate, 2–3 × 1.5 mm, apex entire, acute, often carinate in distal part of spikelet. |
Flowers | perianth bristles present, sometimes rudimentary, brown, length variable, obscurely retrorsely spinulose; anthers brown, 1.7–2.2 mm. |
perianth bristles 3–6, whitish to stramineous, stout to slender, often unequal, from rudimentary to 1/2 of achene length; stamens 3; anthers dark yellow to brown, 0.9–1.4 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, stramineous, rarely dark brown, ovoid to obpyriform, slightly to greatly compressed-trigonous, rarely thickly lenticular, angles prominent or abaxial angle obscure, 0.9–1.2 × 0.65–0.8 mm, apex narrowly to broadly truncate, neck short, often compressed more than body, at 20–30X finely rugulose with more than 20 horizontal ridges in a vertical series or reticulate or cancellate. |
Tubercles | sessile, depressed-pyramidal, often apiculate, as wide as achene, 0.3–0.5 × 0.7–1.1 mm. |
whitish to brown, pyramidal, lower than wide, often 3-lobed as viewed from the top, 0.1–0.3 × 0.4–0.65 mm. |
Eleocharis melanocarpa |
Eleocharis bolanderi |
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Phenology | Fruiting summer. | Fruiting late spring–summer. |
Habitat | Fresh, oligotrophic, acid, sandy or peaty, often drying shores, ponds, ditches | Fresh, often summer-dry meadows, springs, seeps, stream margins |
Elevation | 10–300 m (0–1000 ft) | 1000–3400 m (3300–11200 ft) |
Distribution |
AL; FL; GA; IN; MA; MI; NC; NY; RI; SC; TX; VA
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CA; CO; ID; NV; OR; UT
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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 bolanderi is clearly distinct from E. montevidensis, from which it differs in its dense, tufted habit with short, caudexlike rhizomes, its leaf sheaths without a tooth, its achene and tubercle shapes, and its acute floral scales. Specimens of Eleocharis bolanderi without rhizomes or achenes are easily confused with E. decumbens, which often may be distinguished by culms 0.5–2 mm wide, and spikelets with scales sometimes more than 3 mm long. The tubercles of E. bolanderi are usually poorly developed and much lower than wide; in E. decumbens they are usually well developed and about as high as wide. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 89. | FNA vol. 23. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Melanocarpae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis |
Sibling taxa | ||
Synonyms | E. montevidensis var. bolanderi | |
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York 3: 311. (1836) | A. Gray: Proc. Amer. Acad. Arts 7: 392. (1868) |
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