Eleocharis geniculata |
Eleocharis suksdorfiana |
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bent spike-rush, Canada spikesedge, capitate spike-rush |
Suksdorf spikerush, Suksdorf's spike-rush |
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Habit | Plants tufted, without creeping rhizomes. | Plants perennial; rhizomes 0.5–1.5 mm thick, scales persistent, 5–10 mm, thinly membranous, not fibrous; resting buds absent (non-resting buds on rhizome apex ellipsoid, 10 × 2–5 mm); caudices present, hard, 2 mm thick. |
Culms | to 45 cm × 0.2–1 mm. |
erect, 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–)10–40 cm × 0.5–1.2 mm, firm to hard, finely many-ridged at 10–20X; culm tufts not proximally bulbous. |
Leaves | distal leaf sheaths persistent, firm, distally tightly sheathing, apex acute. |
distal leaf sheaths stramineous to brown or reddish proximally, green to stramineous distally, subtruncate to obtuse, membranous to papery; apex brown to red. |
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. |
5–10 × 2–4 mm; proximal scale usually empty, 3–5 mm, usually 1/2 or more as long as spikelet; floral scales 8–12 per spikelet, lanceolate (to ovate), 3.5–5 × 2–2.5 mm. |
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 6, equal, the longest equaling achene to exceeding tubercle, very slender, spinules dense; anthers 1.6–3.5 mm. |
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. |
medium brown to gray or dark brown, equilaterally trigonous to compressed trigonous, rarely some biconvex, 2–2.7 × 0.7–1.3 mm, apex tapered to a distinct stramineous beak 0.2–0.9 × 0.3–0.6 mm. |
Tubercles | stramineous to whitish, umbonate to subconic, 0.2–0.4 × 0.2–0.5 mm, apex rounded to acute. |
0.4–0.5 × 0.3–0.5 mm. |
2n | = 10. |
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Eleocharis geniculata |
Eleocharis suksdorfiana |
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Phenology | Fruiting spring–winter (Mar–Dec). | Fruiting late spring–summer. |
Habitat | Brackish creeks, canal banks, dune depressions, hammocks, irrigation ditches, lakeshores, lagoons, mangrove thickets, maritime mud flats, ditches, salt marshes | Bogs, fens, wet meadows, springs, wet gravel near ponds |
Elevation | 0–1500 m (0–4900 ft) | (0–)1100–3300 m ((0–)3600–10800 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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CA; CO; ID; MT; NV; OR; UT; WA; AB; BC |
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.) |
Although Eleocharis suksdorfiana is usually included in E. quinqueflora, it clearly differs qualitatively as given in the key. A collection from hot springs in Ruby Valley, Elko County, Nevada, has stout perianth bristles less than half of the achene length and may represent an undescribed taxon related to E. suksdorfiana. Eleocharis suksdorfiana closely resembles E. rostellata in its achenes, tubercles, culms, and caudices; it differs in the presence of long horizontal rhizomes and the absence of stoloniferous culms. The achenes of E. suksdorfiana are often finely longitudinally ridged, but in E. rostellata they are often rugulose. Specimens from Coconino and Santa Cruz counties, Arizona, are probably E. suksdorfiana but lack achenes so cannot be identified with certainty. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 101. | FNA vol. 23, p. 115. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae | Cyperaceae > Eleocharis > subg. Zinserlingia |
Sibling taxa | ||
Synonyms | Scirpus geniculatus, E. capitata, E. caribaea, E. dispar | E. paucifora var. suksdorfiana, E. quinqueflora var. suksdorfiana |
Name authority | (Linnaeus) Roemer & Schultes: in J. J. Roemer et al., Syst. Veg. 2: 150. (1817) | Beauverd: Bull. Soc. Bot. Genève 13: 267. (1922) |
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