Eleocharis quinqueflora |
Eleocharis retroflexa |
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few-flower spike-rush, few-flower spikesedge, éléocharide à cinq fleurs |
coastal plain spikerush |
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Habit | Plants perennial; rhizomes 0.2–1 mm thick, scales persistent or fugaceous, 2–4(–7) mm, thinly membranous, not fibrous; resting buds often present on rhizomes or among culm bases, broadly to narrowly ovoid, 3–6(–10) × 2–5 mm; caudices absent, rarely present, soft or rarely hard, 0.5 mm thick. | Plants annual, tufted, mat-forming, often stoloniferous, sometimes entirely vegetative; rhizomes absent. |
Culms | 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 wider than thick, 5–35 cm × 0.2–0.5(–1.2) mm, soft to hard; culm tufts often proximally bulbous (if bulbous then tunicated by papery-fibrous scales). |
erect, ascending or arching, pentagonal, sulcate, 1.5–10 cm × 0.2–0.3 mm [larger], soft. |
Leaves | distal leaf sheaths stramineous to brown or reddish proximally, green to stramineous or brown distally, membranous to papery, apex often reddish, subtruncate to acute. |
distal leaf sheaths persistent or disintegrating, pale brown to green, red-spotted [mostly red-brown], membranous; apex acuminate. |
Spikelets | 3–8 × 1.5–4 mm; proximal scale with a flower, seldom empty, 2–5 mm, 1/2 or more as long as spikelet; floral scales 3–10 per spikelet, 2.5–6 × 1.5–2.5 mm. |
basal spikelets usually present, bisexual; often proliferous, ellipsoid or obovoid, laterally compressed, 1.7–3.9 × 1.2–2 mm, apex acute; proximal scale empty or with a flower, deciduous, amplexicaulous, similar to floral scales (sometimes 2.4–2.9 mm); subproximal scale with a flower; floral scales clearly distichous, 2–6 [or more], 4–6 per mm of rachilla, pale brown [marked red-brown], ovate or elliptic, 1.8–2.5 × 0.8–1.4 mm, membranous, apex rounded to obtuse, midribs green, keeled. |
Flowers | perianth bristles (0–)3–6, often unequal, rudimentary to equaling tubercle, stout to slender, spinules dense to apparently absent; anthers 1.5–2.7(–3.5) mm. |
perianth bristles 6, colorless or pale brown, shorter than achenes; spinules not evident at 45X; stamens 3; anthers (0.55–)0.7 mm; styles 3-fid. |
Achenes | stramineous to medium brown or gray-brown, equilaterally trigonous to compressed-trigonous, rarely some biconvex, obpyriform (to obovoid), 1.6–2.3 × 0.7–1.3 mm, beak variable. |
stramineous (to cream), obovoid, trigonous or subterete, not compressed, angles prominent, 0.8 × 0.5–0.55 mm, apex not constricted proximal to tubercle, coarsely cancellate or honeycomb-reticulate at 10–15X. |
Tubercles | rarely absent, 0.3–0.4 × 0.2–0.3 mm. |
red-brown, pyramidal, trigonous, proximally clearly to obscurely 3-lobed, lobes decurrent on achene angles, 0.3–0.35 × 0.3–0.4 mm. |
Eleocharis quinqueflora |
Eleocharis retroflexa |
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Phenology | Fruiting (spring–)summer. | Fruiting summer. |
Habitat | Fens, wet meadows, seeps, springs, hot springs | Freshwater ponds, stream banks, marshes, sandy or muddy soils |
Elevation | 0–3600 m (0–11800 ft) | 0–10 m (0–0 ft) |
Distribution |
AK; AZ; CA; CO; IA; ID; IL; IN; MA; ME; MI; MN; MT; NE; NH; NJ; NM; NV; NY; OH; OR; PA; UT; VT; WA; WI; WY; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT; Greenland; Eurasia
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AL; Mexico; Central America; South America; West Indies; Bermuda; Asia (including Indonesia); Pacific Islands; Australia |
Discussion | The chromosome numbers for Eleocharis quinqueflora reported for North America (2n = 80) are in doubt because vouchers and other information are lacking. The often-cited n = 10 is probably erroneous. S.-O. Strandhede and R. M. T. Dahlgren (1968) gave 2n = 132 and 134 from Scandinavia. Recognition of infraspecific taxa within E. quinqueflora is premature pending a worldwide revision of subg. Zinserlingia. It has been reported from North Dakota, although I have not seen specimens. About five varieties and subspecies of E. quinqueflora have been described worldwide. Most specimens from eastern North America and some from the West can be placed in Eleocharis quinqueflora subsp. fernaldii (Svenson) Hultén, which is characterized by its small size (culms to 15 cm × 0.5 mm) and small bulbs. Specimens of E. quinqueflora from 2000–3600 m in California, which are atypical, especially in that the proximal scales of the spikelets do not subtend flowers, may deserve taxonomic recognition. Those plants are also small, with culms only to 15 cm × 0.5 mm; hard caudices are often present at the culm-tuft bases; small, narrowly ovoid bulbs are sometimes present; and perianth bristles are absent or rudimentary. Very few specimens of E. quinqueflora are intermediate with E. suksdorfiana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
We have seen only one collection of Eleocharis retroflexa from the flora area (Mobile, Alabama, in 1896, US). Other populations are likely in the United States Gulf States. The broad-shouldered, strongly sculptured achenes, trilobed, decurrent tubercles, and basal spikelets are distinctive. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 114. | FNA vol. 23, p. 98. |
Parent taxa | Cyperaceae > Eleocharis > subg. Zinserlingia | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Tenuissimae |
Sibling taxa | ||
Synonyms | Scirpus quinqueflorus, E. fernaldii, E. pauciflora, E. pauciflora var. fernaldii, E. quinqueflora subsp. fernaldii | Scirpus retroflexus, Baeothryon retroflexum, Chaetocyperus niveus, Chaetocyperus polymorphus var. depauperatus, Chaetocyperus rugulosus, Chaetocyperus viviparus, Cyperus depauperatus, E. depauperata |
Name authority | (Hartmann) O. Schwarz: Mitt. Thüring. Bot. Ges. 1: 89. (1949) | (Poiret) Urban: Symb. Antill. 2: 165. (1900) |
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