Eleocharis albida |
Eleocharis brachycarpa |
|
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white spikerush |
shortfruit spikerush |
|
Habit | Plants perennial; rhizomes soft, longer internodes 2–4 cm, cortex loose, scales fugaceous, 6 mm, thinly membranous and translucent. | Plants annual, densely cespitose; rhizomes obscured among culm bases, 0.2 mm thick, internodes to 4 mm, scales not evident. |
Culms | not rooting at tips, terete, 10–40 cm, soft to firm, smooth. |
mostly ascending, 4-angled, sulcate, 5 cm × 0.1–0.2 mm, soft. |
Leaves | distal leaf sheaths proximally brownish or sometimes reddish, distally stramineous to green. |
distal leaf sheaths persistent, colorless, translucent, apex narrowly acute. |
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, 2–3 × 1–2 mm, apex blunt; floral scales 10–30, ca. 10 per mm of rachilla, orange-brown to stramineous with broad colorless margin, midrib region stramineous, lanceolate, folded lengthwise, 1.5–2 × 0.8–1 mm, midrib prominent, apex acuminate. |
Flowers | perianth bristles (5–)6(–8), brown, stout, the longer equaling achene or tubercle, retrorsely spinulose; stamens 3; anthers brown, 1 mm. |
perianth bristles absent; anthers 0.7–1.2 mm. |
Achenes | falling with scales, obovoid, angles keeled, 0.8–1 × 0.7–0.8 mm, apex with short neck. |
whitish, broadly obpyriform, much less than 2 times longer than wide, angles and longitudinal ridges ca. 6, obscure, 0.4 × 0.3 mm, apex blunt, trabeculae 20, indistinct, crowded. |
Tubercles | whitish to brown, mammillate to pyramidal, 0.2–0.3 × 0.3–0.35 mm, 1/3 or less as wide as achene. |
brownish, not appressed, mostly pyramidal, 0.1 × 0.1 mm. |
Eleocharis albida |
Eleocharis brachycarpa |
|
Phenology | Fruiting summer. | Fruiting winter–spring. |
Habitat | Coastal saltmarsh edges, sloughs, beaches, dune depressions, ditches | Wet soils |
Elevation | 0 m (0 ft) | 0–20 m (0–100 ft) |
Distribution |
AL; FL; GA; LA; MD; MS; NC; NM; SC; TX; Mexico; Bermuda
|
TX; Mexico (Tamaulipas) |
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.) |
Of conservation concern. Eleocharis brachycarpa is unique among the North American members of subg. Scirpidium in its floral scales, which are markedly spreading in fruit, often apparently decussate when pressed, narrowly lanceolate, and folded lengthwise so that they do not press open and flat. It is apparently very rare and local. It is admitted to the flora only on the basis of labels on a paratype (Berlandier 996) and on Berlandier 2426, both of which read “In locis paludosis – De Matamoros a las Nueces [River, Texas], Ap. 1834.” H. K. Svenson (1929) mistranscribed the locality “Nueces,” publishing it as “Mueres.” We have also seen a specimen from Mexico, Tamaulipas, 24 mi. N of San Fernando, edges of resacas, elev. 15 m, 1959, M.C. Johnston 4882C (TEX). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 99. | FNA vol. 23, p. 111. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Albidae | Cyperaceae > Eleocharis > subg. Scirpidium |
Sibling taxa | ||
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York. 3: 304. (1836) | Svenson: Rhodora 31: 200, plate 190, fig. 34. (1929) |
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