Cyperus reflexus |
Cyperus pseudothyrsiflorus |
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bentawn flatsedge |
flatsedge |
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Habit | Herbs, perennial, cespitose; rhizomes elongate, scaly, 2–3 mm wide. | Herbs, perennial, cespitose, rhizomatous. |
Culms | roundly trigonous to terete, 30–80 cm × 1–1.6 mm, glabrous. |
trigonous, base thickened, tuberous, 15–40 cm × 2–2.6 mm, glabrous. |
Leaves | 1–6, 10–40 cm, glabrous or essentially so. |
flat to V-shaped, 10–30 cm × (3–)4–5.8 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, densely oblong to ellipsoid, 10–20 × 10–20 mm; rays 4–12, 10–20 cm bracts 3–6, horizontal to ascending at 30°, V-shaped, 3–15 cm × (3–)4(–5.8) mm; rachilla deciduous, wings persistent, 0.5–0.7 mm wide. |
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). |
(5–)10–20(–30), linear to oblong, quadrangular, (2.2–)4–12(–16) × 0.7–1.2 mm, densly packed on rachis with 11–21 spikelets per 5 mm rachis; distal spikelet spreading or ascending; floral scales persistent, 1–5, appressed, laterally whitish to reddish brown, medially green, narrowly oblong to ovate, laterally 3–6-ribbed, 2.4–3.4 × 1.6–2 mm, apex rounded to ± acute, entire, mucronate, mucro 0.1–0.3 mm; sterile terminal scale, involute, only 0.4–0.6 mm wide with mucro 0.2–0.5 mm. |
Flowers | stamen 1; anthers 0.6–1 mm; styles 0.3–0.5 mm; stigmas 0.3–0.6 mm. |
anthers (0.3–)0.4–0.7 mm; styles 0.4–0.5 mm; stigmas 0.5–0.9 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. |
light brown, sessile to slightly stipitate, ellipsoid to narrowly ellipsoid to narrowly obovoid, 1.4–1.9 × 0.5–0.75 mm, apex slightly apiculate, surfaces puncticulate. |
Cyperus reflexus |
Cyperus pseudothyrsiflorus |
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Phenology | Fruiting late spring–fall (May–Oct). | Fruiting mid summer–early fall (Jul–Sep). |
Habitat | Muddy soils or shallow waters | Damp, disturbed soils, croplands |
Elevation | 0–200 m (0–700 ft) | 0–1000 m (0–3300 ft) |
Distribution |
FL; LA; OK; TX; Mexico; Central America (Costa Rica) |
TX; Mexico |
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. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. arenicola, C. fraternus, C. pseudovegetus var. arenicola, C. reflexus var. fraternus | C. uniflorus var. pseudothyrsiflorus |
Name authority | Vahl: Enum. Pl. 2: 299. (1805) | (Kükenthal) J. Rich. Carter & S. D. Jones: Rhodora 99: 330. (1998) |
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