Cyperus reflexus |
Cyperus sanguinolentus |
|
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bentawn flatsedge |
purpleglume flatsedge |
|
Habit | Herbs, perennial, cespitose; rhizomes elongate, scaly, 2–3 mm wide. | Herbs, perennial; rhizomes ± horizontal, to 12 cm × 0.8–1.2 mm. |
Culms | roundly trigonous to terete, 30–80 cm × 1–1.6 mm, glabrous. |
± terete to roundly trigonous, 3–25(–60) cm × 0.3–2 mm, glabrous. |
Leaves | 1–6, 10–40 cm, glabrous or essentially so. |
1–3, V-shaped, 1–8(–15) cm × 1–2 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. |
spike 1, loosely ovoid, 7–14 × 8–20 mm; rays (0–)1–4, to 2(–3) cm; bracts 2–4, horizontal to ascending at 30(–45)°, V-shaped to flat, 1–8(–18) cm × 0.5–1.5(–2) 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). |
3–5(–14), oblong to linear-lanceoloid, 8–18 × 2–2.6(–3) mm; floral scales (6–)10–26(–32), laterally clear to light brown, sometimes with purplish margins, medially light brown, 2-keeled, laterally ribless, medially 2–3-ribbed, oblong to ovate, 1.9–2.2(–2.7) × 1.8–2.3 mm, apex obtuse. |
Flowers | stamen 1; anthers 0.6–1 mm; styles 0.3–0.5 mm; stigmas 0.3–0.6 mm. |
stamens 3; anthers ellipsoid, 0.3–0.6 mm, connective not prolonged; styles 0.6–1 mm; stigmas 1–1.5 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, ± stipitate, obovoid to ovoid, 1–1.4 × 0.6–0.8 mm, apex truncate, apiculate, surfaces minutely punctate. |
Cyperus reflexus |
Cyperus sanguinolentus |
|
Phenology | Fruiting late spring–fall (May–Oct). | Fruiting late summer–fall. |
Habitat | Muddy soils or shallow waters | Emergent shorelines, ditches |
Elevation | 0–200 m (0–700 ft) | 20 m (100 ft) |
Distribution |
FL; LA; OK; TX; Mexico; Central America (Costa Rica) |
AL; GA; LA; MS; Asia; Africa [Introduced in North America] |
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.) |
Cyperus sanguinolentus is the only rhizomatous, distigmatic Cyperus in the eastern United States. An early collection from Louisiana was described as C. louisianensis, supposedly endemic. Recent field work and morphometric studies convincingly showed it to be an introduction of the Asian C. sanguinolentus) (J. R. Carter and C. T. Bryson 2001. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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 | C. louisianensis, Pycreus sanguinolentus |
Name authority | Vahl: Enum. Pl. 2: 299. (1805) | Vahl: Enum. Pl. 2: 351. (1805) |
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