Eleocharis obtusa |
Eleocharis bernardina |
|
---|---|---|
blunt spike-rush, blunt spikesedge, broad spike spikerush, egg-shape spike-rush, éléocharide obtuse |
fewflower spikerush |
|
Habit | Plants perennial; rhizomes 0.5–1 mm thick, scales persistent, 5–8 mm, membranous, not fibrous; resting buds absent (non-resting buds on rhizome apex ellipsoid, 10 × 2–5 mm); caudices present, hard, 1–2 mm thick. | |
Culms | 3–50(–90) cm × 0.2–2 mm. |
markedly arched, not spirally twisted, not contracted near spikelet, when dry usually with several blunt to acute ridges and sulcate, subterete to slightly compressed, to 2 times as wide as thick, 5–15 cm × 0.5–1 mm, firm to hard; culm tufts not proximally bulbous. |
Leaves | apex of distal leaf sheath obtuse to acute, tooth to 0.3 mm. |
distal leaf sheaths brown to reddish proximally, stramineous to reddish distally, apex sometimes reddish, membranous to papery. |
Spikelets | broadly ovoid (to ellipsoid or lanceoloid), apex rounded (to acute), (2–)5–13 × (2–)3–4 mm; floral scales 15–150+, 8–20 per mm of rachilla, orange-brown (to stramineous), elliptic, 1.5–2.5 × 1–1.5 mm, midribs seldom keeled, apex broadly rounded. |
3–6 × 2–4 mm; proximal scale empty, 2.5–4 mm, 1/2 or more as long as spikelet; floral scales 4–9 per spikelet, 3.5–5 × 2 mm. |
Flowers | perianth bristles (5–)6–7, rarely 0, brown, stout, slightly to usually greatly exceeding tubercle; stamens usually 3; anthers brown to yellow, 0.3–0.6 mm; styles usually 3-fid and 2-fid in same spikelet. |
perianth bristles 4–7, very unequal, some shorter than 1/2 of achene, stout and smooth, others equaling or exceeding tubercle, very slender and densely spinulose; anthers 1–1.5 mm. |
Achenes | 0.9–1.2(–1.3) × 0.7–0.9 mm. |
medium brown, equilaterally trigonous to compressed trigonous or some biconvex, 1.5–2.1 × 0.9–1.2 mm, beak 0.2–0.3 × 0.3–0.4 mm. |
Tubercles | deltoid 0.35–0.5 × (0.4–)0.5–0.8 mm, 1/3–2/3 as high as wide, 1/3–1/2 as high and 2/3–9/10 as wide as achene. |
0.25–0.5 × 0.15–0.2 mm. |
2n | = 10. |
|
Eleocharis obtusa |
Eleocharis bernardina |
|
Phenology | Fruiting summer–fall. | Fruiting summer. |
Habitat | Fresh shores, marshes, disturbed places | Wet meadows in conifer forests |
Elevation | 10–1600 m [30–5200 ft] | 2100–2700 m [6900–8900 ft] |
Distribution |
AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; ME; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; WY; HI; BC; NS; ON; PE; QC
|
CA |
Discussion | Extremely uncommon plants of Eleocharis obtusa without perianth bristles may be called E. obtusa var. peasei (type from New Hampshire). Robust plants with distinct caudices, floral scales 2.5 mm, and achenes 1.2–1.3 mm (Eleocharis obtusa var. gigantea Fernald) are rare (specimens seen from the Washington-British Columbia border [type], Arkansas, and the Hawaiian Islands). Dwarf plants (E. obtusa var. jejuna Fernald, type from Maine), with unusually small achenes and floral scales, and tubercles often less than 0.5 mm wide, are occasional in the East and are easily confused with E. ovata and E. aestuum. A few specimens are intermediate with E. engelmannii. Eleocharis obtusa is sometimes treated as conspecific with E. ovata, which consistently differs in its mostly 2-fid styles, mostly two stamens, and especially its narrower tubercles (B. M. H. Larson and P. M. Catling 1996). Eleocharis macounii Fernald has been treated as a synonym of E. obutsa (H. K. Svenson 1957) but is more probably a hybrid between E. intermedia and E. obtusa (P. M. Catling and S. G. Hay 1993; see 34. E. intermedia). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Although usually included in Eleocharis quinqueflora, E. bernardina is clearly more like E. suksdorfiana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 105. | FNA vol. 23. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Scirpus obtusus, E. obtusa var. ellipsoidales, E. obtusa var. gigantea, E. obtusa var. jejuna, E. obtusa var. peasei | Scirpus bernardinus, E. pauciflora var. bernardina, E. quinqueflora var. bernardina |
Name authority | (Willdenow) Schultes: Mant. 2: 89. (1824) | (Munz & I. M. Johnston) Munz: Man. S. Calif. Bot., 68, 597. (1935) |
Web links |
|