Eleocharis atropurpurea |
Eleocharis vivipara |
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purple spike-rush |
sprouting spike-rush, umbrella hairgrass, viviparous spike-rush |
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Habit | Plants tufted, without creeping rhizomes. | 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 | 2–12(–19) cm × 0.2–0.4 mm. |
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 firm, distally tightly sheathing, apex acute. |
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 to ellipsoid, 2–6(–8) × 1–2.5 mm, apex acute; proximal scale with or without flower, not amplexicaulous; floral scales to 100, 15–19 per mm of rachilla, often loosely appressed, dark red-brown to stramineous, ovate to elliptic, 0.6–1.3 × 0.3–0.7 mm, membranous, apex rounded to acute. |
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 (0–)4–6, typically 4, colorless to whitish, vestigial to 1/2 as long as achene, smooth or spinuliferous; styles 2-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 | black, obovoid, biconvex, 0.3–0.5 × 0.3–0.4 mm, apex often constricted proximal to tubercle, smooth at 40X. |
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 | stramineous to whitish, umbonate to subconic, 0.1–0.2 × 0.1–0.2 mm, apex acute. |
whitish, gray, brown, or greenish black, pyramidal, trigonous, 0.2–0.5 × 0.4–0.5 mm. |
2n | = 20. |
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Eleocharis atropurpurea |
Eleocharis vivipara |
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Phenology | Fruiting summer–fall (Jun–Sep). | Fruiting spring–fall. |
Habitat | Canal banks, hammocks, irrigation ditches, lake and pond margins, maritime shores, rice fields | Sandy and peaty soils, ditches, pond margins, shallow waters bordering pine-flatwoods and pine-palmetto scrub |
Elevation | 0–1800 m (0–5900 ft) | 0–80 m (0–300 ft) |
Distribution |
AL; CA; FL; GA; IA; KS; LA; MI; MO; NC; NE; NM; OK; SC; TX; WA; BC; Mexico; Central America; South America; West Indies; Europe (naturalized); Asia; Africa; Pacific Islands
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AL; FL; GA; LA; NC; SC; VA
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Discussion | Eleocharis atropurpurea has been reported from Colorado, Montana, and Virginia; I have not seen voucher specimens. (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, p. 102. | FNA vol. 23, p. 93. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Synonyms | Scirpus atropurpureus | Chlorocharis vivipara, E. curtisii |
Name authority | (Retzius) J. Presl & C. Presl: in C. B. Presl, Reliq. Haenk. 1: 196. (1828) | Link: Hort. Berol. 1: 283. (1827) |
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