Eleocharis atropurpurea |
Eleocharis minima |
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purple spike-rush |
small spikerush |
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Habit | Plants tufted, without creeping rhizomes. | Plants annual, tufted, often mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent. |
Culms | 2–12(–19) cm × 0.2–0.4 mm. |
erect, ascending or arching, quadrangular, sulcate, 1–13 cm × 0.1–0.3 mm, soft. |
Leaves | distal leaf sheaths firm, distally tightly sheathing, apex acute. |
distal leaf sheaths persistent or disintegrating, red-brown, stramineous, green, or mottled red-brown, translucent, apex narrowly acute. |
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 often present, bisexual; often proliferous, ovoid or ellipsoid, laterally compressed when young, but terete at maturity, 2–7 × 1–2.6 mm, acute; proximal scale empty, often persistent, amplexicaulous, similar to floral scales; subproximal scale with a flower; floral scales spirodistichous (superficially appearing ± spiraled), (4–)10–28, 6–9 per mm of rachilla, pale brown, mottled red-brown to purple, ovate or elliptic, 1.3–2.1 × 0.7–1 mm, membranous, midribs green and red-brown, 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 6, colorless, white, or stramineous, slightly shorter than to equaling achene, spinules retrorse, acute; stamens 3; anthers 0.4–0.5 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. |
greenish or pale brown or red-brown, often clearly spotted greenish or red-brown, ellipsoid to obovoid, trigonous (or terete?), angles prominent (keeled), 0.6–0.8 × 0.4–0.5 mm, apex constricted proximal to tubercle, smooth. |
Tubercles | stramineous to whitish, umbonate to subconic, 0.1–0.2 × 0.1–0.2 mm, apex acute. |
red-brown, pyramidal, trigonous, 0.1–0.3 × 0.2–0.4 mm. |
2n | = 20. |
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Eleocharis atropurpurea |
Eleocharis minima |
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Phenology | Fruiting summer–fall (Jun–Sep). | Fruiting mid spring–fall. |
Habitat | Canal banks, hammocks, irrigation ditches, lake and pond margins, maritime shores, rice fields | Freshwater, sandy and peaty shores of lakes, muddy areas |
Elevation | 0–1800 m (0–5900 ft) | 0–400 m (0–1300 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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FL; MD; TX; Mexico; South America; West Indies; Central America (Costa Rica, El Salvador, Guatemala, Nicaragua, Panama) |
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.) |
Eleocharis minima is most often confused with E. bicolor and E. baldwinii (see comments under 33. E. bicolor). Although floral scales in E. minima often superficially appear to be spirally disposed, in reality they are spirodistichous, ± decussate, while in E. baldwinii they are strictly distichous in one plane. The number of floral scales per millimeter is much greater in E. minima than in E. baldwinii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 102. | FNA vol. 23, p. 97. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Synonyms | Scirpus atropurpureus | Chaetocyperus jamesonii, Chaetocyperus polymorphus, Chaetocyperus viviparus, E. durandii, E. jamesonii, E. minima var. ambigua, E. oropuchensis, E. savannarum, E. subtilis, E. tenuissima, E. villaricensis, E. wrightiana, Isolepis ambigua |
Name authority | (Retzius) J. Presl & C. Presl: in C. B. Presl, Reliq. Haenk. 1: 196. (1828) | Kunth: Enum. Pl. 2: 139. (1837) |
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