Eleocharis parvula |
Eleocharis atropurpurea |
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dwarf spikerush, dwarf spikesedge, little-head spike-rush, little-head spikesedge, small spike-rush, éléocharide naine |
purple spike-rush |
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Habit | Plants tufted, without creeping rhizomes. | |
Culms | 2–12(–19) cm × 0.2–0.4 mm. |
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Leaves | distal leaf sheaths firm, distally tightly sheathing, apex acute. |
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Spikelets | 2–4 × 1–2 mm, sometimes absent in deeper water; proximal scale 1/2 or more of spikelet length; floral scales 6–10 per spikelet, 1.4–2.7 mm, commonly entirely stramineous, apex rounded to subacute. |
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. |
Flowers | perianth bristles 6, stramineous, fairly stout to slender, usually equaling achene to slightly exceeding tubercle, sometimes unequal and some 1/2 of achene, very rarely rudimentary, minutely retrorsely spinulose; anthers 0.7–1.2 mm. |
perianth bristles (0–)4–6, typically 4, colorless to whitish, vestigial to 1/2 as long as achene, smooth or spinuliferous; styles 2-fid. |
Achenes | stramineous, sometimes pale brown, obovoid to obpyriform, thickly trigonous, angles distinct, faces concave to plane, rarely convex, 0.9–1.2 × 0.55–0.75 mm, apex tapered, smooth or faintly rough at 30X. |
black, obovoid, biconvex, 0.3–0.5 × 0.3–0.4 mm, apex often constricted proximal to tubercle, smooth at 40X. |
Tubers | terminating rhizomes usually markedly J- or horseshoe-shaped, body (apart from apical bud) oblong, 2–2.5(–5) × 0.5–1 mm; tubers among culm bases straight, narrowly fusiform, 4–5 mm. |
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Tubercles | 0.1–0.2 × 0.15 mm. |
stramineous to whitish, umbonate to subconic, 0.1–0.2 × 0.1–0.2 mm, apex acute. |
2n | = 10 (Europe). |
= 20. |
Eleocharis parvula |
Eleocharis atropurpurea |
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Phenology | Fruiting summer–fall (north) or late winter–fall (far south). | Fruiting summer–fall (Jun–Sep). |
Habitat | Brackish or saline, mostly coastal tidal marshes, shores, mud flats, swamps, ponds, ditches | Canal banks, hammocks, irrigation ditches, lake and pond margins, maritime shores, rice fields |
Elevation | 0–600 m (0–2000 ft) | 0–1800 m (0–5900 ft) |
Distribution |
AL; AR; CA; CT; FL; GA; IL; IN; KS; LA; MA; MD; ME; MI; MO; MS; NC; NJ; NY; OH; OR; SC; VA; WA; BC; NB; NL; NS; QC; Mexico; Central America (Nicaragua); Eurasia
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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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Discussion | Plants without well-developed bristles are otherwise typical Eleocharis parvula. S.-O. Strandhede and R. M. T. Dahlgren (1968) provided a detailed description from Scandinavia; the mostly curved tubers of North American plants are differently shaped than the ovoid, mostly nearly straight tubers illustrated by them. Eleocharis parvula is very uncommon inland. Plants lacking spikelets and having rather broad culms with evident aerenchyma (E. parvula forma spongiosa Fassett) that are submerged in tidal zones closely resemble small plants of Sagittaria graminea. Eleocharis parvula has also been reported from North Dakota, South America, and Africa; I have not seen specimens. Plants without achenes or tubers cannot be reliably identified to species. Literature reports from Cuba, Mexico, and Venezuela may be based on specimens of E. coloradoensis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 23, p. 106. | FNA vol. 23, p. 102. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Parvulae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae |
Sibling taxa | ||
Synonyms | Scirpus parvulus, E. pygmaea, S. nanus | Scirpus atropurpureus |
Name authority | (Roemer & Schultes) Link ex Bluff Nees: Comp. Fl. German. ed. 2, 1: 93. (1836) | (Retzius) J. Presl & C. Presl: in C. B. Presl, Reliq. Haenk. 1: 196. (1828) |
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