Eleocharis atropurpurea |
Eleocharis suksdorfiana |
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purple 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 | 2–12(–19) cm × 0.2–0.4 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 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 | ovoid to ellipsoid, 2–6(–8) × 1–2.5 mm, apex acute; proximal scale with or without flower, not amplexicaulous; floral scales to 100, 15–19 per mm of rachilla, often loosely appressed, dark red-brown to stramineous, ovate to elliptic, 0.6–1.3 × 0.3–0.7 mm, membranous, 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–)4–6, typically 4, colorless to whitish, vestigial to 1/2 as long as achene, smooth or spinuliferous; 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 | black, obovoid, biconvex, 0.3–0.5 × 0.3–0.4 mm, apex often constricted proximal to tubercle, smooth 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, 0.1–0.2 × 0.1–0.2 mm, apex acute. |
0.4–0.5 × 0.3–0.5 mm. |
2n | = 20. |
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Eleocharis atropurpurea |
Eleocharis suksdorfiana |
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Phenology | Fruiting summer–fall (Jun–Sep). | Fruiting late spring–summer. |
Habitat | Canal banks, hammocks, irrigation ditches, lake and pond margins, maritime shores, rice fields | Bogs, fens, wet meadows, springs, wet gravel near ponds |
Elevation | 0–1800 m (0–5900 ft) | (0–)1100–3300 m ((0–)3600–10800 ft) |
Distribution |
AL; CA; FL; GA; IA; KS; LA; MI; MO; NC; NE; NM; OK; SC; TX; WA; BC; Mexico; Central America; South America; West Indies; Europe (naturalized); Asia; Africa; Pacific Islands
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CA; CO; ID; MT; NV; OR; UT; WA; AB; BC |
Discussion | Eleocharis atropurpurea has been reported from Colorado, Montana, and Virginia; I have not seen voucher specimens. (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. 102. | FNA vol. 23, p. 115. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleogenus > ser. Maculosae | Cyperaceae > Eleocharis > subg. Zinserlingia |
Sibling taxa | ||
Synonyms | Scirpus atropurpureus | E. paucifora var. suksdorfiana, E. quinqueflora var. suksdorfiana |
Name authority | (Retzius) J. Presl & C. Presl: in C. B. Presl, Reliq. Haenk. 1: 196. (1828) | Beauverd: Bull. Soc. Bot. Genève 13: 267. (1922) |
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