Eleocharis geniculata |
Eleocharis microcarpa |
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bent spike-rush, Canada spikesedge, capitate spike-rush |
small-fruit spikesedge, smallfruit spikerush |
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Habit | Plants tufted, without creeping rhizomes. | Plants usually annual, tufted, sometimes mat-forming via proliferating and arching inflorescences (stoloniferous), sometimes entirely vegetative; rhizomes absent. | ||||
Culms | to 45 cm × 0.2–1 mm. |
often ascending or arching, quadrangular or broadly elliptic, 2–40 cm × 0.1–0.4(–0.6) mm, soft. |
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Leaves | distal leaf sheaths persistent, firm, distally tightly sheathing, apex acute. |
distal leaf sheaths persistent or disintegrating, pale brown, green or red-brown, streaked or mottled red-brown or purple, translucent, membranous, apex narrowly acute. |
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Spikelets | orbicular to ovoid, 1–9 × 1–4 mm, apex rounded to acute; proximal scale without flower, not amplexicaulous; floral scales to 125, 11–14 per mm of rachilla, tightly appressed, dark red-brown to stramineous, ovate to elliptic, 0.8–3 × 0.6–2(–2.3) mm, membranous to cartilaginous, apex rounded to acute. |
basal spikelets absent; often proliferous, ovoid to ellipsoid or lanceoloid, terete, 2–10.7 × 1–2 mm, apex acute; proximal scale empty, persistent, amplexicaulous, dissimilar to floral scales, often longer, often resembling an involucral bract, ovate to lanceolate, midrib markedly thickened and broad and often prolonged beyond lamina; subproximal scale with flower; floral scales spiraled, colorless, whitish, or pale brown, streaked or mottled red-brown or purple, midribs green and red-brown or green and purple, ovate to elliptic, 0.8–1.5 × 0.4–0.8 mm, membranous, midrib obscure to prominent. |
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Flowers | perianth bristles (0–)4–8, typically 7, red-brown, rarely whitish, vestigial to much exceeding tubercle, typically equaling achene, spinules few to dense; styles 2-fid. |
perianth bristles present or sometimes apparently absent; stamens 3; anthers 0.15–0.35; styles 3-fid. |
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Achenes | brown ripening to black, biconvex, orbicular to obpyriform, 0.5–1.1 × 0.3–0.7 mm, apex rarely constricted proximal to tubercle, very finely reticulate at 40X. |
whitish to olive or pale brown, sometimes spotted olive or red-brown, obovoid, trigonous (or subterete), angles prominent, 0.55–0.8 × 0.3–0.5 mm, apex constricted proximal to tubercle, smooth. |
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Tubercles | stramineous to whitish, umbonate to subconic, 0.2–0.4 × 0.2–0.5 mm, apex rounded to acute. |
green or pale brown to red-brown, trigonous. |
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2n | = 10. |
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Eleocharis geniculata |
Eleocharis microcarpa |
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Phenology | Fruiting spring–winter (Mar–Dec). | |||||
Habitat | Brackish creeks, canal banks, dune depressions, hammocks, irrigation ditches, lakeshores, lagoons, mangrove thickets, maritime mud flats, ditches, salt marshes | |||||
Elevation | 0–1500 m [0–4900 ft] | |||||
Distribution |
AL; AZ; CA; FL; GA; IL; IN; LA; MI; MS; NE; NM; NV; OH; OK; PA; TX; ON; Mexico; Central America; South America; West Indies; Bermuda; Asia; Africa; Pacific Islands
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AL; FL; GA; IN; LA; MA; MD; MI; MS; NC; NJ; PA; SC; TN; TX; VA; West Indies
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Discussion | The name Eleocharis caribaea (Rottbøll) S. F. Blake is considered by most contemporary authorities to be misapplied (K. L. Wilson 1990). Eleocharis geniculata has been reported from South Carolina; I have not seen a voucher. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). Specimens of Eleocharis brittonii and E. microcarpa without achenes are often difficult to distinguish. More detailed study of the four apparent entities across the two species is warranted. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 23, p. 101. | FNA vol. 23, p. 95. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Scirpus geniculatus, E. capitata, E. caribaea, E. dispar | |||||
Name authority | (Linnaeus) Roemer & Schultes: in J. J. Roemer et al., Syst. Veg. 2: 150. (1817) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 312. (1836) | ||||
Web links |