Eleocharis atropurpurea |
Eleocharis parishii |
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purple spike-rush |
Parish spikerush, Parish's spike rush |
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Habit | Plants tufted, without creeping rhizomes. | Plants perennial, mat-forming; rhizomes evident, long, 0.5–1(–2) mm thick, firm, cortex persistent, longer internodes 5–30 mm, scales often fugaceous, 5–10 mm, membranous, not fibrous. |
Culms | 2–12(–19) cm × 0.2–0.4 mm. |
terete or cross section elliptic (or rectangular), usually with to 8 blunt ridges when dry, 10–50 cm × 0.2–0.7(–1) mm, soft to firm, spongy. |
Leaves | distal leaf sheaths firm, distally tightly sheathing, apex acute. |
distal leaf sheaths persistent, not splitting, mostly proximally dark red, distally red to brown or green, thinly papery to thickly membranous, apex usually redbrown, subtruncate to obtuse or subacute, callose, tooth often present on most or all culms, to 1 mm. |
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. |
narrowly lanceoloid (to narrowly cylindric), 3–20 × 1.5–2.5 mm, apex acute; proximal scale amplexicaulous, entire; subproximal scale empty or with flower; floral scales appressed or spreading in fruit, 15–40, 3–4 per mm of rachilla, orange brown, midrib regions often greenish, ovate, 2–3 × 1 mm, apex entire, rounded to obtuse in proximal part of spikelet, acute in distal part, carinate, at least in distal part of spikelet. |
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 3–7, rarely apparently absent, stramineous to whitish, slender to stout, often unequal, rudimentary to slightly exceeding tubercle; stamens 3; anthers yellow to stramineous, 1.1–2 mm; styles 3-fid, 0.3–0.4 × 0.2–0.3 mm. |
Achenes | black, obovoid, biconvex, 0.3–0.5 × 0.3–0.4 mm, apex often constricted proximal to tubercle, smooth at 40X. |
falling with scales, yellow-brown or dark brown, ellipsoid or obovoid to obpyriform, compressed-trigonous, angles evident to obscure, rarely prominent, 0.8–1.4 × 0.5–0.7 mm, neck absent to long, smooth or sometimes minutely cancellate at 20–30X. |
Tubercles | stramineous to whitish, umbonate to subconic, 0.1–0.2 × 0.1–0.2 mm, apex acute. |
whitish, pyramidal, often higher than wide, 0.3–0.4 × 0.25–0.35 mm. |
2n | = 20. |
= 10. |
Eleocharis atropurpurea |
Eleocharis parishii |
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Phenology | Fruiting summer–fall (Jun–Sep). | Fruiting spring–fall. |
Habitat | Canal banks, hammocks, irrigation ditches, lake and pond margins, maritime shores, rice fields | Fresh to brackish, wet soil or emergent, often drying lakeshores, ponds, streams, springs |
Elevation | 0–1800 m (0–5900 ft) | 500–2300 m (1600–7500 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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AZ; CA; KS; NM; NV; OR; TX; UT; Mexico
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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 parishii is very similar to E. montevidensis, with which it sometimes grows. It differs from E. montevidensis mainly in its narrowly lanceoloid to cylindric spikelets and its floral scale apices not recurved or horizontally wrinkled. Some apparent intermediates occur in regions of sympatry. The floral scales of E. montevidensis are more densely placed on the rachilla. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 102. | FNA vol. 23, p. 80. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis |
Sibling taxa | ||
Synonyms | Scirpus atropurpureus | E. disciformis, E. montevidensis var. disciformis, E. montevidensis var. parishii |
Name authority | (Retzius) J. Presl & C. Presl: in C. B. Presl, Reliq. Haenk. 1: 196. (1828) | Britton: J. New York Microscop. Soc. 5: 110. (1889) |
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