Eleocharis albida |
Eleocharis retroflexa |
|
---|---|---|
white spikerush |
coastal plain spikerush |
|
Habit | Plants perennial; rhizomes soft, longer internodes 2–4 cm, cortex loose, scales fugaceous, 6 mm, thinly membranous and translucent. | Plants annual, tufted, mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent. |
Culms | not rooting at tips, terete, 10–40 cm, soft to firm, smooth. |
erect, ascending or arching, pentagonal, sulcate, 1.5–10 cm × 0.2–0.3 mm [larger], soft. |
Leaves | distal leaf sheaths proximally brownish or sometimes reddish, distally stramineous to green. |
distal leaf sheaths persistent or disintegrating, pale brown to green, red-spotted [mostly red-brown], membranous; apex acuminate. |
Spikelets | ovoid to oblong-subcylindric, 4–12 × 2–3.5 mm, apex acute to rounded; proximal scale empty, clasping 1/2 of culm, like floral scales; subproximal 1 or 2 scales often empty; floral scales 20–100, 10 per mm of rachilla, entirely stramineous or sometimes red-brown, ovate, (1.5–)2–2.5 × 1.5 mm, apex broadly rounded, entire. |
basal spikelets usually present, bisexual; often proliferous, ellipsoid or obovoid, laterally compressed, 1.7–3.9 × 1.2–2 mm, apex acute; proximal scale empty or with a flower, deciduous, amplexicaulous, similar to floral scales (sometimes 2.4–2.9 mm); subproximal scale with a flower; floral scales clearly distichous, 2–6 [or more], 4–6 per mm of rachilla, pale brown [marked red-brown], ovate or elliptic, 1.8–2.5 × 0.8–1.4 mm, membranous, apex rounded to obtuse, midribs green, keeled. |
Flowers | perianth bristles (5–)6(–8), brown, stout, the longer equaling achene or tubercle, retrorsely spinulose; stamens 3; anthers brown, 1 mm. |
perianth bristles 6, colorless or pale brown, shorter than achenes; spinules not evident at 45X; stamens 3; anthers (0.55–)0.7 mm; styles 3-fid. |
Achenes | falling with scales, obovoid, angles keeled, 0.8–1 × 0.7–0.8 mm, apex with short neck. |
stramineous (to cream), obovoid, trigonous or subterete, not compressed, angles prominent, 0.8 × 0.5–0.55 mm, apex not constricted proximal to tubercle, coarsely cancellate or honeycomb-reticulate at 10–15X. |
Tubercles | whitish to brown, mammillate to pyramidal, 0.2–0.3 × 0.3–0.35 mm, 1/3 or less as wide as achene. |
red-brown, pyramidal, trigonous, proximally clearly to obscurely 3-lobed, lobes decurrent on achene angles, 0.3–0.35 × 0.3–0.4 mm. |
Eleocharis albida |
Eleocharis retroflexa |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Coastal saltmarsh edges, sloughs, beaches, dune depressions, ditches | Freshwater ponds, stream banks, marshes, sandy or muddy soils |
Elevation | 0 m (0 ft) | 0–10 m (0–0 ft) |
Distribution |
AL; FL; GA; LA; MD; MS; NC; NM; SC; TX; Mexico; Bermuda
|
AL; Mexico; Central America; South America; West Indies; Bermuda; Asia (including Indonesia); Pacific Islands; Australia |
Discussion | In most spikelets, the bright brown stigmas contrast strikingly with the stramineous floral scales. We have not seen vouchers for H. K. Svenson’s (1937) reports of Eleocharis albida from Virginia. The collections we have seen from Maryland are from the 1800s. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
We have seen only one collection of Eleocharis retroflexa from the flora area (Mobile, Alabama, in 1896, US). Other populations are likely in the United States Gulf States. The broad-shouldered, strongly sculptured achenes, trilobed, decurrent tubercles, and basal spikelets are distinctive. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 99. | FNA vol. 23, p. 98. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Albidae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Synonyms | Scirpus retroflexus, Baeothryon retroflexum, Chaetocyperus niveus, Chaetocyperus polymorphus var. depauperatus, Chaetocyperus rugulosus, Chaetocyperus viviparus, Cyperus depauperatus, E. depauperata | |
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York. 3: 304. (1836) | (Poiret) Urban: Symb. Antill. 2: 165. (1900) |
Web links |