Eleocharis bella |
Eleocharis ambigens |
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beautiful spikerush, delicate spikerush, pretty spikerush |
ambiguous spikesedge, éléocharide ambiquë |
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Habit | Plants annual, rarely perennial, usually densely tufted; rhizomes rarely evident, 0.2–0.3 mm thick, internodes 1–5 mm, scales not evident. | Plants perennial, mat-forming; rhizomes evident, long, 1–2 mm thick, firm, cortex persistent, longer internodes 1–3 cm, scales persistent, 5–10 mm, membranous, not fibrous. |
Culms | often ascending or spreading, 4-angled or sometimes terete, sometimes sulcate, 1–7 cm × 0.2–0.3 mm, soft to firm. |
terete, often with to 16 blunt ridges when dry, 25–80 cm × 0.5–1.5 mm, firm, internally spongy. |
Leaves | sheaths stramineous, distal sheaths often splitting abaxially, slightly inflated distally, oblique, apex acute. |
distal leaf sheaths persistent, not splitting, proximally dark red, distally red to stramineous or green, often callose, thinly papery (to membranous), apex dark red-brown, obtuse to subtruncate, tooth sometimes present on some culms, to 0.3 mm. |
Spikelets | ovoid, 1.5–4 × 0.8–2 mm, apex acute; floral scales 4–15, 8 per mm of rachilla, colorless or reddish brown, midrib region green, ovate-lanceolate, not folded lengthwise, 1–1.5 × 0.5–0.7 mm, mibrib obscure to somewhat keeled, apex narrowly acute to acuminate, slightly recurved. |
ovoid to lanceoloid, 5–23 × 2–3(–4) mm, apex acute (to obtuse); proximal scale amplexicaulous, entire; subproximal scale with flower; floral scales often spreading in fruit, 10–60, 3–4 per mm of rachilla, medium brown, rarely red-brown, midrib regions mostly stramineous to green, in proximal part of spikelet ovate, in distal part lanceolate, 2.5–3.5 × 1.7 mm, entire, apex acute to rarely obtuse, often carinate in distal part of spikelet. |
Flowers | perianth bristles absent; anthers 0.3–0.5 mm. |
perianth bristles 2–4(–5), brown, slender to stout, usually very unequal, rudimentary to equaling achene; stamens 3; anthers brown, 1.5–2 mm; styles 2-fid, sometimes some 3-fid. |
Achenes | with angles and longitudinal ridges ca. 6–10, rather prominent, broadly ovoid, less than 2 times longer then wide, (0.55–)0.65–0.75 × 0.3–0.4 mm, apex blunt, trabeculae distinct, 20–30. |
not persistent, dark yellow or stramineous, obovoid to obpyriform, all biconvex or some (very rarely all) compressedtrigonous, angles obscure, 1–1.5 × 0.9–1.25 mm, apex rounded, neck absent (to very short), finely rugulose at 10–20X, with 20 or more horizontal ridges in vertical series and/or finely cancellate at 10–30X. |
Tubercles | grayish, mostly appressed, pyramidal, often depressed, 0.1–0.2 × 0.1–0.25 mm. |
brown or proximally whitish, pyramidal, depressed, rarely some as high as wide, 0.15–0.3(–0.5) × (0.3–)0.4–0.6 mm. |
2n | = 44, 45, 46. |
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Eleocharis bella |
Eleocharis ambigens |
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Phenology | Fruiting spring–summer. | Fruiting spring–summer. |
Habitat | Bare, often drying soil of stream alluvium, lake margins, wet meadows | Coastal (rarely inland) fresh to brackish pond shores, marshes, disturbed places |
Elevation | 200–2900 m (700–9500 ft) | 0–10 m (0–0 ft) |
Distribution |
AZ; CA; ID; MT; NM; NV; OR; WA; Mexico (Chihuahua)
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CT; FL; GA; LA; MA; MS; NC; NJ; RI; SC; TX; VA; QC |
Discussion | Eleocharis bella and E. acicularis seem to be amply distinct; putative hybrids are unknown. The occasional plants of E. bella with evident rhizomes, which include the type, are otherwise identical to plants apparently without rhizomes. Eleocharis bella is very similar to E. cancellata. There is an Illinois collection from Peoria in 1901, from the alluvial banks of the Illinois River. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eleocharis ambigens is usually treated as a synonym of E. fallax because some specimens from Massachusetts to Georgia have some 3-fid styles and some obscurely trigonous achenes. A specimen of E. ambigens from Louisiana has trigonous achenes. Eleocharis ambigens is very similar to and perhaps better included in E. uniglumis (S.-O. Strandhede 1967). Intermediates with E. macrostachya occur in Louisiana and Texas. The depressed tubercles are diagnostic of E. ambigens. Eleocharis ambigens is sometimes confused with E. montevidensis, which is readily distinguished by its floral scales with broadly rounded apices. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 110. | FNA vol. 23, p. 78. |
Parent taxa | Cyperaceae > Eleocharis > subg. Scirpidium | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis |
Sibling taxa | ||
Synonyms | E. acicularis var. bella, E. acicularis var. minima | |
Name authority | (Piper) Svenson: Rhodora 31: 201. (1929) | Fernald: Rhodora 37: 394. (1935) |
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