Eleocharis bella |
Eleocharis obtusetrigona |
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beautiful spikerush, delicate spikerush, pretty spikerush |
spikerush |
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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; rhizomes 3–4 mm thick, soft to hard, longer internodes 3–8 cm, scales more than 1 cm, tubers absent. |
Culms | often ascending or spreading, 4-angled or sometimes terete, sometimes sulcate, 1–7 cm × 0.2–0.3 mm, soft to firm. |
obscurely 3–5-angled to terete, 40–110 cm × (2–)3.6–7.5 mm, soft, not septate-nodulose, internally spongy, transverse septa incomplete; plants never forming filiform, flaccid culms. |
Leaves | sheaths stramineous, distal sheaths often splitting abaxially, slightly inflated distally, oblique, apex acute. |
distal leaf sheaths persistent, membranous, apex acute to long-acuminate, sometimes prolonged into a slender bladelike portion to 6 cm. |
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. |
not proliferous, 12–43 × 3.5–6 mm; rachilla joints bearing obscure winglike remnants of floral scales; proximal scale without a flower, amplexicaulous, 3.6–7.5 mm; floral scales 30–125, 1–3 per mm of rachilla, greenish to pale brown, often with pale to dark brown submarginal band or a subapical darker spot, ovate to oblong, 4.3–5.8 × 2.5–3.3 mm, cartilaginous, often membranous toward margins, margins broadly translucent, membranous, apex rounded to acute. |
Flowers | perianth bristles absent; anthers 0.3–0.5 mm. |
perianth bristles 6–7, stramineous, margins and spinules reddish to pale brown, stout, flattened, subequal, exceeding achene, 2.5–3.2 mm, coarsely retrorsely spinulose; anthers reddish brown, 1.5–1.9 mm; styles 3-fid or sometimes 2-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. |
pale brown, biconvex, obpyriform, 1.7–2.3 × 1.2–1.5 mm, clearly sculptured at 10–15X, each face with 10–15 rows of transversely elongated cells, often isodiametric at achene base, apex usually constricted to neck 0.5–0.6 mm wide. |
Tubercles | grayish, mostly appressed, pyramidal, often depressed, 0.1–0.2 × 0.1–0.25 mm. |
stramineous, lamelliform to high-pyramidal, 0.8–1.1 × 0.7–0.9 mm. |
Eleocharis bella |
Eleocharis obtusetrigona |
|
Phenology | Fruiting spring–summer. | Fruiting spring–fall. |
Habitat | Bare, often drying soil of stream alluvium, lake margins, wet meadows | Fresh, permanent water in ditches |
Elevation | 200–2900 m (700–9500 ft) | 0–20 m (0–100 ft) |
Distribution |
AZ; CA; ID; MT; NM; NV; OR; WA; Mexico (Chihuahua)
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TX; e Mexico; South America; Central America (Nicaragua) |
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.) |
In North America Eleocharis obtusetrigona is known from only five collections, two of them originally identified as E. fistulosa (Poiret) Link [= E. acutangula (Roxburgh) Schultes], which is common in Mexico and South America. The original description of E. obtusetrigona is poor and does not clearly distinguish E. obtusangula from E. acutangula. H. K. Svenson (1939) included E. obtusetrigona in E. acutangula, which can be distinguished by its acutely trigonous culms as well as its smaller floral scales and achenes. The tubercles are often spongy as in E. quadrangulata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 110. | FNA vol. 23, p. 118. |
Parent taxa | Cyperaceae > Eleocharis > subg. Scirpidium | Cyperaceae > Eleocharis > subg. Limnochloa |
Sibling taxa | ||
Synonyms | E. acicularis var. bella, E. acicularis var. minima | Limnochloa obtusetrigona, E. fistulosa var. obtusetrigona, E. mutata var. obtusetrigona |
Name authority | (Piper) Svenson: Rhodora 31: 201. (1929) | (Lindley & Nees) Steudel: Syn. Pl. Glumac. 2: 80. (1855) |
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