Eleocharis albida |
Eleocharis decumbens |
|
---|---|---|
white spikerush |
decumbent spikerush |
|
Habit | Plants perennial; rhizomes soft, longer internodes 2–4 cm, cortex loose, scales fugaceous, 6 mm, thinly membranous and translucent. | Plants perennial, densely tufted; rhizomes often hidden by culms and roots, fairly long, 3–4 mm thick, hard, cortex persistent, longer internodes from very short to 5 mm, scales usually clearly evident, disintegrating to fibers, 20–25 mm, papery. |
Culms | not rooting at tips, terete, 10–40 cm, soft to firm, smooth. |
terete, often with 10–18 blunt ridges when dry, 10–50 cm × 0.3–2 mm, firm to rigid, spongy. |
Leaves | distal leaf sheaths proximally brownish or sometimes reddish, distally stramineous to green. |
distal leaf sheaths persistent, not splitting, proximally brown or reddish, distally stramineous, brown, reddish or green, often inflated, papery, apex mostly dark red-brown, subtruncate to obtuse, often callose, tooth absent. |
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. |
ovoid, 3–8 × 2–2.5 mm, apex acute; proximal scale amplexicaulous, entire; subproximal scale empty or with flower; floral scales appressed in fruit, 10–20, 3 per mm of rachilla, orange-brown, midrib regions often greenish, ovate, 3–3.5 × 1.5 mm, apex entire, acute, often carinate in distal part of spikelet. |
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, stramineous, stout, nearly equal, mostly equaling or exceeding tubercle, (0.5–)1–2.2 mm, prominently retrorsely spinulose; stamens 3(?); anthers dark yellow to stramineous, 1.2–1.5; styles 3-fid. |
Achenes | falling with scales, obovoid, angles keeled, 0.8–1 × 0.7–0.8 mm, apex with short neck. |
falling with scales, dark brown, obpyriform, nearly eqilaterally- to greatly compressed-trigonous, angles slightly prominent, 1–1.3 × 0.75–0.9 mm, neck absent or short, finely rugulose at 20X with more than 20 horizontal ridges in vertical series, or reticulate or cancellate at 20–30X. |
Tubercles | whitish to brown, mammillate to pyramidal, 0.2–0.3 × 0.3–0.35 mm, 1/3 or less as wide as achene. |
well developed, whitish, pyramidal, as high as wide to much lower than wide, 0.2–0.6 × 0.4–0.7 mm. |
Eleocharis albida |
Eleocharis decumbens |
|
Phenology | Fruiting summer. | Fruiting summer–fall. |
Habitat | Coastal saltmarsh edges, sloughs, beaches, dune depressions, ditches | Wet fresh meadows, seeps, and lakeshores, in interior montane conifer forests and alpine zones |
Elevation | 0 m (0 ft) | 700–3500 m (2300–11500 ft) |
Distribution |
AL; FL; GA; LA; MD; MS; NC; NM; SC; TX; Mexico; Bermuda
|
CA; OR |
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.) |
Eleocharis decumbens is known only from Shasta and Tulare counties in California. Although Eleocharis decumbens has long been ignored or treated as a variety of E. montevidensis, it clearly is a very distinct species, from which it differs especially in its thick rhizomes with fibrous scales and its acute floral scales. Specimens of Eleocharis decumbens without rhizomes or achenes are easily confused with the apparently closely related E. bolanderi, which often may be distinguished by culms no more than 0.5 mm wide and spikelets with scales no more than 3 mm long. The tubercles of E. decumbens are usually well differentiated from the achenes and about as high as wide; the tubercles of E. bolanderi are often poorly developed and much lower than wide. Three collections from Jackson and Klamath counties in Oregon, lack achenes but are probably E. decumbens. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 99. | FNA vol. 23. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Albidae | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis |
Sibling taxa | ||
Synonyms | E. montevidensis var. decumbens | |
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York. 3: 304. (1836) | C. B. Clarke: Bull. Misc. Inform., addit. ser. 8: 23. (1908) |
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