Eleocharis bolanderi |
Eleocharis vivipara |
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Bolander's spikerush |
sprouting spike-rush, umbrella hairgrass, viviparous spike-rush |
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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. | Plants perennial, short-rhizomatous, forming dense clumps, often entirely vegetative; rhizomes caudexlike, ascending, internodes and scales hidden by crowded culms and sheaths, 0.5 mm thick. |
Culms | subterete, often with to 6 prominent ridges when dry, sulcate, 10–30 cm × 0.3–0.5 mm, firm to rigid, spongy. |
often arching, often sering as stolons, broadly elliptic, (4–)7–38(–45) cm × (0.1–)0.3–0.7 mm, soft to firm. |
Leaves | 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. |
distal leaf sheaths persistent or disintegrating, yellowish to pale brown, sometimes mottled or wholly red-brown, membranaous to papery, apex acute to narrowly obtuse. |
Spikelets | 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. |
basal spikelets absent; usually proliferous, ovoid to ellipsoid to linear or terete, 3.3–9.6 × 1.2–2.3 mm, apex acute; proximal scale empty, persistent, amplexicaulous, similar to floral scales (usually slightly longer, midrib broadly green); subproximal scale with a flower; floral scales spiraled, 5–25, 4–8 per mm of rachilla, pale brown, usually spotted, streaked or mottled red-brown to purple, midribs green or green and red-brown, elliptic to obovate, 1.8–2.7 × 1–1.5 mm, membranous to chartaceous (papery), midrib evident to prominent, apex rounded to obtuse. |
Flowers | 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. |
perianth bristles 5–6, red-brown (proximally often white), shorter than to equaling tubercle, rarely longer, 0.9–1.3(–2) mm; spinules sparse, retrorse, sharply acute; stamens 3; anthers yellow, 0.8–1.8 mm; styles 3-fid. |
Achenes | 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. |
gray or greenish, obovoid or obpyriform, trigonous, angles very prominent, 0.6–0.9 × 0.55–0.8 mm, apex constricted proximal to tubercle, finely honeycomb-reticulate at 10–20X, each face with 20 or more rows of evident enlarged cells. |
Tubercles | whitish to brown, pyramidal, lower than wide, often 3-lobed as viewed from the top, 0.1–0.3 × 0.4–0.65 mm. |
whitish, gray, brown, or greenish black, pyramidal, trigonous, 0.2–0.5 × 0.4–0.5 mm. |
Eleocharis bolanderi |
Eleocharis vivipara |
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Phenology | Fruiting late spring–summer. | Fruiting spring–fall. |
Habitat | Fresh, often summer-dry meadows, springs, seeps, stream margins | Sandy and peaty soils, ditches, pond margins, shallow waters bordering pine-flatwoods and pine-palmetto scrub |
Elevation | 1000–3400 m (3300–11200 ft) | 0–80 m (0–300 ft) |
Distribution |
CA; CO; ID; NV; OR; UT
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AL; FL; GA; LA; NC; SC; VA
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Discussion | 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.) |
Most specimens of Eleocharis vivipara are from Florida. Identification of vegetative (often aquatic) specimens is sometimes tentative. Eleocharis vivipara is often confused with E. microcarpa and E. brittonii, and sometimes with E. baldwinii. The red-spotted band at the sheath apex and the gray, cancellate achenes are characteristic of E. vivipara. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23. | FNA vol. 23, p. 93. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Synonyms | E. montevidensis var. bolanderi | Chlorocharis vivipara, E. curtisii |
Name authority | A. Gray: Proc. Amer. Acad. Arts 7: 392. (1868) | Link: Hort. Berol. 1: 283. (1827) |
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