Eleocharis baldwinii |
Eleocharis atropurpurea |
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Baldwin's spike-rush |
purple spike-rush |
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Habit | Plants annual(?), often mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent. | Plants tufted, without creeping rhizomes. |
Culms | often arching, sometimes spotted or streaked red-brown, quadrangular or broadly elliptic, sulcate or not, 0.5–25(–30) cm × 0.1–0.4 mm, soft. |
2–12(–19) cm × 0.2–0.4 mm. |
Leaves | distal leaf sheaths persistent or disintegrating, stramineous, green, red-brown, or spotted or streaked red-brown, membranous, translucent, apex obtuse or acute. |
distal leaf sheaths firm, distally tightly sheathing, apex acute. |
Spikelets | basal spikelets usually present, pistillate; often proliferous, ovoid, ellipsoid, or linear, clearly laterally compressed, 2.3–6.9 × 0.5–2 mm, apex acute, proximal scale empty, amplexicaulous, similar to floral scales (midribs sometimes more prominent and sometimes slightly prolonged beyond lamina); subproximal scale with a flower; floral scales clearly distichous, 3–9, 3–4 per mm of rachilla, yellowish, pale brown, or red-brown, spotted, streaked, or mottled red-brown, narrowly ovate to oblong, (1.5–)2–5 × 0.4–0.6(–1.2) mm, membranous, apex rounded, obtuse or rarely acute, midribs keeled. |
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. |
Flowers | perianth bristles 3–7, incurved, colorless, white, or red-brown, shorter than or equaling achene; spinules sparse, retrorse, sharply acute; stamens 3; anthers 1.4–2.2 mm; styles 3-fid. |
perianth bristles (0–)4–6, typically 4, colorless to whitish, vestigial to 1/2 as long as achene, smooth or spinuliferous; styles 2-fid. |
Achenes | whitish or greenish, spotted dark green, obovoid, trigonous, angles prominent, 0.6–0.9 × 0.4–0.6 mm, apex constricted proximal to tubercle, smooth to finely cancellate at 10–20X. |
black, obovoid, biconvex, 0.3–0.5 × 0.3–0.4 mm, apex often constricted proximal to tubercle, smooth at 40X. |
Tubercles | pale to red-brown, pyramidal, trigonous, 0.2–0.3(–0.4) × 0.2–0.5 mm. |
stramineous to whitish, umbonate to subconic, 0.1–0.2 × 0.1–0.2 mm, apex acute. |
2n | = 20. |
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Eleocharis baldwinii |
Eleocharis atropurpurea |
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Phenology | Fruiting early spring–winter. | Fruiting summer–fall (Jun–Sep). |
Habitat | Freshwater to moist terrestrial sites, pine savannas, cypress ponds, lakeshores | Canal banks, hammocks, irrigation ditches, lake and pond margins, maritime shores, rice fields |
Elevation | 0–60 m (0–200 ft) | 0–1800 m (0–5900 ft) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; SC; TX
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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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Discussion | Coarse plants of Eleocharis baldwinii usually bear more achenes per spikelet, dark colored achenes, culms gray-green when dried, and yellowish sheaths. Finer plants often bear few achenes per spikelet, whitish achenes, culms that are mid green when dried, and reddish sheaths. Achene color may relate to maturity, with darker achenes being fully mature. Although these variants appear to intergrade, they may be recognizable taxonomically. The longer floral scales in the spikelet are usually 3.5– 5 mm. We have not seen vouchers to verify the report of Eleocharis baldwinii from Virginia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 23, p. 98. | FNA vol. 23, p. 102. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae |
Sibling taxa | ||
Synonyms | Chaetocyperus baldwinii | Scirpus atropurpureus |
Name authority | (Torrey) Chapman: Fl. South. U.S., 519. (1860) | (Retzius) J. Presl & C. Presl: in C. B. Presl, Reliq. Haenk. 1: 196. (1828) |
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