Eleocharis baldwinii |
Eleocharis reverchonii |
|
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Baldwin's spike-rush |
Reverchon's spikerush |
|
Habit | Plants annual(?), often mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent. | Plants perennial; rhizomes sometimes not evident, 0.3–0.5 mm thick, internodes 3–11 mm, scales not evident. |
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. |
sometimes arched, smooth or obscurely 4- or 5-angled or -ridged, terete or slightly compressed, 6–25 cm × 0.15–0.3 mm, soft to firm. |
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 persistent, red proximally, colorless distally, closely sheathing, apex blunt. |
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, 2–6 × 1–2 mm, apex acute; scales 5–15, 5 per mm of rachilla, bright red-brown, midrib region green to stramineous, ovate, 1.5–1.7 × 1 mm, midrib keeled to obscure, apex blunt 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 absent; anthers 0.5–1 × 0.2 mm. |
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. |
with angles plus longitudinal ridges ca. 8–9, obscure to rather prominent, obovoid to obpyriform, much less than 2 times longer than wide, 0.55–0.6 × 0.3–0.4 mm, trabeculae 20–30, rather obscure and crowded. |
Tubercles | pale to red-brown, pyramidal, trigonous, 0.2–0.3(–0.4) × 0.2–0.5 mm. |
brownish to whitish, pyramidal to depressed, 0.1–0.15 × 0.1–0.2 mm. |
Eleocharis baldwinii |
Eleocharis reverchonii |
|
Phenology | Fruiting early spring–winter. | Fruiting late winter–spring (Feb–Apr). |
Habitat | Freshwater to moist terrestrial sites, pine savannas, cypress ponds, lakeshores | Wet soil of ponds, marshes, grasslands, ditches |
Elevation | 0–60 m (0–200 ft) | 10–200 m (0–700 ft) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; SC; TX
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TX |
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.) |
Of conservation concern. Eleocharis reverchonii perhaps should be treated as a variety or subspecies of E. acicularis. One collection (three sheets at KSC) from Calhoun county in southeastern Texas is apparently the only known example within E. subg. Scirpidium with proliferous spikelets. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 98. | FNA vol. 23, p. 110. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae | Cyperaceae > Eleocharis > subg. Scirpidium |
Sibling taxa | ||
Synonyms | Chaetocyperus baldwinii | |
Name authority | (Torrey) Chapman: Fl. South. U.S., 519. (1860) | Svenson: Rhodora 31: 203, fig. 27. (1929) |
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