Cyperus reflexus |
Cyperus diandrus |
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bentawn flatsedge |
umbrella flat sedge |
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Habit | Herbs, perennial, cespitose; rhizomes elongate, scaly, 2–3 mm wide. | Herbs, annual, cespitose, with fibrous roots. |
Culms | roundly trigonous to terete, 30–80 cm × 1–1.6 mm, glabrous. |
trigonous, 4–25(–35) cm, glabrous. |
Leaves | 1–6, 10–40 cm, glabrous or essentially so. |
flat, 5–20 cm × 1.5–3 mm. |
Inflorescences | heads ovoid to pyramidal, 9–15 mm diam.; rays 0 or 3–6, 0.5–4 cm, glabrous; bracts 3–4, longest erect, appearing as continuation of culm, others horizontal to ascending, 4–17 cm × 1.5–4 mm. |
heads ± digitate, 12–22 mm diam.; rays 3–6, 1–6 cm; bracts 1–4, ± horizontal, flat, 1.5–15 cm × 1.5–3 mm. |
Spikelets | 25–60, reddish with contrasting yellowish or greenish edges, oblong-lanceoloid, strongly compressed, 5–6(–15) × 1.5–2.5 mm; floral scales 10–22, laterally reddish, medially yellowish green, 2-keeled, laterally strongly 1-ribbed on each side, proximally grooved, ovate-elliptic, 1.4–2.2 × 0.8–1.5 mm, apex acute, apically scabridulous (sometimes glabrous). |
6–12, oblong-lanceoloid, compressed, 5–10 × 2.8–3.2 mm; floral scales 8–28, closely imbricate, stramineous to light brown or clear (marginal band bright red, spikelet thus appearing dark margined), laterally ribless, oblong to ovate, 2.5–3 × 1.6–1.9 mm. |
Flowers | stamen 1; anthers 0.6–1 mm; styles 0.3–0.5 mm; stigmas 0.3–0.6 mm. |
stamens 2(–3); anthers 0.3 mm, connective apex reddish, subulate, 0.1–0.2 mm; styles 0.3–0.5 mm; stigmas 2.2–3.1 mm. |
Achenes | reddish brown, stipitate, ovoid-ellipsoid, 0.8–0.9 × 0.3–0.4 mm, stipe 0.1–0.2 mm, apex acute to acuminate, surfaces reticulate or subtly rugulose. |
brown, network of ridges forming isodiametric or square cells, sessile or stipitate, obovoid to ovoid, 1–1.2 × 0.5–0.6 mm, stipe, if present, 0.1 mm, apex obtuse, apiculate, surfaces minutely punctate. |
Cyperus reflexus |
Cyperus diandrus |
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Phenology | Fruiting late spring–fall (May–Oct). | Fruiting summer. |
Habitat | Muddy soils or shallow waters | Emergent shorelines, in sandy, peaty, or slightly brackish areas (though seldom where disturbed) |
Elevation | 0–200 m (0–700 ft) | 0–600 m (0–2000 ft) |
Distribution |
FL; LA; OK; TX; Mexico; Central America (Costa Rica) |
CT; DE; IA; IL; IN; MA; MD; ME; MI; MN; MO; NE; NH; NJ; NY; PA; RI; VA; VT; NB; NS; ON; QC
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Discussion | Cyperus reflexus is recognized by its reddish scales with contrasting greenish or yellow keels and by the laterally 1ribbed scales. The lateral rib is most often situated where the reddish and yellowish parts of the scale meet. Two varieties of C. reflexus, var. reflexus and var. fraternus, have been recognized (M. F. Denton 1978b). Both varieties were noted as intermingled in the North American and South American segments of the widely disjunct range of C. reflexus. Such variation does not seem significant at the varietal level (see G. C. Tucker 1994; G. C. Tucker and R. McVaugh 1993). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23. | FNA vol. 23, p. 161. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Pycreus |
Sibling taxa | ||
Synonyms | C. arenicola, C. fraternus, C. pseudovegetus var. arenicola, C. reflexus var. fraternus | Pycreus diander |
Name authority | Vahl: Enum. Pl. 2: 299. (1805) | Torrey: Cat. Pl. New York, 90. (1819) |
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