Eleocharis atropurpurea |
Eleocharis retroflexa |
|
---|---|---|
purple spike-rush |
coastal plain spikerush |
|
Habit | Plants tufted, without creeping rhizomes. | Plants annual, tufted, mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent. |
Culms | 2–12(–19) cm × 0.2–0.4 mm. |
erect, ascending or arching, pentagonal, sulcate, 1.5–10 cm × 0.2–0.3 mm [larger], soft. |
Leaves | distal leaf sheaths firm, distally tightly sheathing, apex acute. |
distal leaf sheaths persistent or disintegrating, pale brown to green, red-spotted [mostly red-brown], membranous; apex acuminate. |
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 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 (0–)4–6, typically 4, colorless to whitish, vestigial to 1/2 as long as achene, smooth or spinuliferous; styles 2-fid. |
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 | black, obovoid, biconvex, 0.3–0.5 × 0.3–0.4 mm, apex often constricted proximal to tubercle, smooth at 40X. |
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 | stramineous to whitish, umbonate to subconic, 0.1–0.2 × 0.1–0.2 mm, apex acute. |
red-brown, pyramidal, trigonous, proximally clearly to obscurely 3-lobed, lobes decurrent on achene angles, 0.3–0.35 × 0.3–0.4 mm. |
2n | = 20. |
|
Eleocharis atropurpurea |
Eleocharis retroflexa |
|
Phenology | Fruiting summer–fall (Jun–Sep). | Fruiting summer. |
Habitat | Canal banks, hammocks, irrigation ditches, lake and pond margins, maritime shores, rice fields | Freshwater ponds, stream banks, marshes, sandy or muddy soils |
Elevation | 0–1800 m (0–5900 ft) | 0–10 m (0–0 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
|
AL; Mexico; Central America; South America; West Indies; Bermuda; Asia (including Indonesia); Pacific Islands; Australia |
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.) |
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. 102. | FNA vol. 23, p. 98. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Synonyms | Scirpus atropurpureus | Scirpus retroflexus, Baeothryon retroflexum, Chaetocyperus niveus, Chaetocyperus polymorphus var. depauperatus, Chaetocyperus rugulosus, Chaetocyperus viviparus, Cyperus depauperatus, E. depauperata |
Name authority | (Retzius) J. Presl & C. Presl: in C. B. Presl, Reliq. Haenk. 1: 196. (1828) | (Poiret) Urban: Symb. Antill. 2: 165. (1900) |
Web links |
|