Eleocharis montevidensis |
Eleocharis aestuum |
|
---|---|---|
Montevideo spike rush, sand spikerush |
tidal spikerush, tidal spikesedge |
|
Habit | Plants perennial, mat-forming; rhizomes evident, long, 0.7–2 mm thick, firm, cortex persistent, longer internodes 1–2 cm, scales often fugaceous, 6–8 mm, membranous, not fibrous. | |
Culms | terete or cross section elliptic or rectangular, with 5–10 blunt ridges when dry, 25–50 cm × 0.5–1.2 mm, firm to hard, spongy. |
often spreading or declining, 3–30 cm × 0.5–1 mm. |
Leaves | distal leaf sheaths persistent, not splitting, mostly proximally dark red, distally red to brown or green, thinly papery, apex usually red-brown, often callose, subtruncate to obtuse, tooth usually present on some or all culms, to 0.9 mm. |
apex of distal leaf sheath obtuse, tooth to 0.2(–0.5) mm. |
Spikelets | usually ovoid or ellipsoid to subcylindric, rarely lanceoloid, 4–12 × (1.5–)2–3 mm, apex rounded to acute; proximal scale amplexicaulous or clasping over 3/4 of culm, entire; subproximal scale empty or with flower; floral scales appressed in fruit, 30–100, 6–10 per mm of rachilla, orange-brown, midrib regions often greenish, oblong to ovate, 1.5–2.5 × 1–1.5 mm, apex entire, broadly rounded, sometimes acute in distal part of spikelet, usually horizontally wrinkled and recurved, often carinate in distal part of spikelet. |
ellipsoid to ovoid, 3–10 × 2–4 mm, apex blunt to subacute; floral scales 10–100+, 10 per mm of rachilla, colorless to pale brownish except for green midrib, 1.5–2 × 1 mm, midribs not keeled, apex rounded. |
Flowers | perianth bristles 5–6(–7), stramineous to medium brown, stout, often unequal, much shorter than to equaling achene, rarely all rudimentary; stamens 3; anthers dark yellow to stramineous, 0.8–1.5 mm; styles 3-fid or some 2-fid. |
perianth bristles absent or 2–4, stramineous or whitish, shorter than to nearly 1/2 achene, very slender, without spinules; stamens 2(–3); anthers 0.3–0.5 mm; styles 2-fid or some 3-fid. |
Achenes | falling with scales, dark brown, obovoid to obpyriform, compressed trigonous, angles evident to obscure, 0.7–1 × 0.65–0.8 mm, neck absent to sometimes long, finely rugulose at 10–30X, over 20 horizontal ridges in vertical series, and/or minutely cancellate at 20–30X. |
0.75–1 × 0.6–0.8 mm. |
Tubercles | brown to whitish, pyramidal, as high as wide or sometimes greatly depressed, (0.1–)0.25–0.3 × 0.2–0.3 mm. |
deltoid, 0.2–0.3 × 0.35–0.45(–0.55) mm, 1/2–3/4as high as wide, 1/4–1/3 as high and 1/2–2/3(–4/5) as wide as achene. |
2n | = 20. |
|
Eleocharis montevidensis |
Eleocharis aestuum |
|
Phenology | Fruiting spring–fall. | Fruiting summer–fall (Jul–Oct). |
Habitat | Wet soil, fresh ponds, lakes, streams, springs, seeps, marshes, ditches, grasslands | Fresh tidal river shores |
Elevation | 0–2300 m (0–7500 ft) | 0–10 m (0–0 ft) |
Distribution |
AL; AZ; CA; FL; KS; LA; MS; NC; NM; OK; SC; TX; Mexico; South America
|
CT; DE; MA; ME; NJ; NY; PA |
Discussion | The name Eleocharis montana was long misapplied to E. montevidensis. The type of E. palmeri, recognized as a species (H. K. Svenson 1957), is indistinguishable from specimens of E. montevidensis. Eleocharis montevidensis is extremely variable; the broadly rounded, usually wrinkled and recurved floral scales are diagnostic. Achenes often fail to form. Eleocharis montevidensis is apparently closely related to E. parishii, in which the floral scales are less densely placed on the rachilla and acute to rounded, and the spikelets are narrowly lanceoloid to cylindric. In the absence of achenes and rhizomes, some specimens of E. montevidensis are easily mistaken for E. tricostata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eleocharis aestuum is very similar to E. diandra and E. ovata; E. diandra differs from E. aestuum in its lower tubercles, brown floral scales, and absence of perianth bristles; E. ovata differs as given in the key to species. D. M. Hines (1975) described E. aestuum using the epithet “palidostachys” [ined.]. Specimens from shores of the Lake-of-the-Woods in Minnesota, and a reservoir and farm in Hardin and Fayette counties, Tennessee, may be referable to E. aestuum. The only recent records of E. aestuum are from the Androscoggin and Kennebec rivers in Maine and the Hudson River in New York (A. Haines 2001). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 80. | FNA vol. 23, p. 104. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Ovatae |
Sibling taxa | ||
Synonyms | E. arenicola, E. montana subsp. montevidensis, E. palmeri | |
Name authority | Kunth: Enum. Pl. 2: 144. (1837) | Hines ex A. Haines: Novon 11: 45. (2001) |
Web links |