Eleocharis tricostata |
Eleocharis rostellata |
|
---|---|---|
three-angle spikerush, three-angle spikesedge |
beak spike-rush, beak spikesedge, walking sedge, walking spikerush |
|
Habit | Plants perennial, mat-forming; rhizomes evident, fairly long, 1.5–3 mm thick, hard, cortex persistent, longer internodes 1.5–3 mm, scales disintegrating to fibers, 4–5 mm, papery. | Plants densely tufted, mat-forming by means of rooting culm tips. |
Culms | terete, often with 8–12 blunt ridges when dry, 20–55 cm × 0.3–1.3 mm, soft to hard. |
1.5–3 times as wide as thick, 20–100 cm × 0.35–2 mm, firm to hard, wiry, with to 8 subacute ribs, rarely nearly smooth; some culms arching or decumbent and rooting at tips. |
Leaves | distal leaf sheaths persistent, rarely splitting, proximally red to stramineous, distally green to reddish, papery, apex often dark reddish, subtruncate to obtuse, not callose, tooth present on some or all culms of plant, to 0.5 mm. |
distal leaf sheaths not splitting abaxially, proximally dark red to brown, apex usually reddish. |
Spikelets | cylindric to ovoid, 5–20 × 2–3 mm, apex rounded to subacute; proximal scale amplexicaulous, apex entire; subproximal scale empty; floral scales appressed in fruit, 20–200+, 10 per mm of rachilla, dark brown, midrib regions often stramineous or greenish, oblong, 1.7–2.5 × 1 mm, apex entire, broadly rounded, usually recurved, mostly carinate. |
ovoid, 5–17 × 2.5–5 mm, apex acute; spikelets on stolons rudimentary, non-flowering, proliferous when rooting; proximal scale empty, amplexicaulous, ovate, 2–4 mm; subproximal scale with flower; floral scales 20–40, 2–3 per mm of rachilla, stramineous to medium brown, midrib region paler, ovate, 3.5–6 × 2–3 mm, membranous to cartilaginous, apex entire, rounded to subacute. |
Flowers | perianth bristles absent; stamens 3; anthers dark yellow, 1–1.5 mm; styles 3-fid. |
perianth bristles brown, equaling achene or tubercle, densely spinulose; anthers brown, 2–2.4 mm. |
Achenes | falling with scales, medium to dark brown, obovoid to obpyriform, with short neck, thickly trigonous, angles prominent (keeled), 0.7–0.9 × 0.4–0.6 mm, obscurely to clearly rugulose at 10–20X with more than 20 horizontal ridges in vertical series and/or minutely cancellate at 20–30X. |
often very variable within one plant, ovoid to obovoid or obpyriform, 1.5–2.5 × 1–1.2 mm, beak to 1 × 0.6 mm. |
Tubercles | brown, rudimentary, mostly apiculate, sometimes pyramidal, 0.05–0.15 × 0.15–0.2 mm. |
when present pale to dark brown, pyramidal, to 0.5 × 0.3 mm. |
Eleocharis tricostata |
Eleocharis rostellata |
|
Phenology | Fruiting late spring–summer. | Fruiting late spring in south, summer–fall in north. |
Habitat | Wet sandy or peaty depressions, pond margins, pine barrens, savannas, mostly coastal plains | Very wet calcareous or brackish fens, springs, shores |
Elevation | 10–200 m (0–700 ft) | 50–2400 m (200–7900 ft) |
Distribution |
AL; FL; GA; MA; MI; NC; NJ; NY; SC; VA
|
AZ; CA; CT; DE; FL; ID; IL; IN; KS; LA; MA; MD; ME; MI; MN; MT; NC; NE; NJ; NM; NV; NY; OH; OK; PA; RI; SC; SD; TX; UT; VA; WA; WI; WY; BC; NS; ON; Mexico; West Indies (Cuba, Haiti, Puerto Rico)
|
Discussion | I have not seen specimens to verify reports of Eleocharis tricostata from Louisiana. In the absence of rhizomes and achenes, E. tricostata is easily mistaken for E. montevidensis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eleocharis rostellata is highly competitive, often forming large monospecific colonies. The South American E. platypus C. B. Clarke is often treated as a synonym of E. rostellata. Eleocharis rostellata superfically closely resembles E. suksdorfiana in its culms, spikelets, and achenes, but differs in the absence of creeping rhizomes, presence of stoloniferous culms, absence of a flower in the proximal scale, and achene surface details. The collection of E. rostellata I have seen from Miami-Dade County, Florida, is from 1877. I have not seen vouchers for Archuleta County, Colorado, by H. D. Harrington (1954), or for the localities in Montana and South Carolina, which are based on the map in H. K. Svenson (1934). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 88. | FNA vol. 23, p. 90. |
Parent taxa | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Eleocharis | Cyperaceae > Eleocharis > subg. Eleocharis > sect. Eleocharis > ser. Rostellatae |
Sibling taxa | ||
Synonyms | Scirpus rostellatus | |
Name authority | Torrey: Ann. Lyceum Nat. Hist. New York. 3: 310. (1836) | (Torrey) Torrey: Fl. New York 2: 347. (1843) |
Web links |
|