Cyperus entrerianus |
Cyperus retrorsus |
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woodrush flatsedge |
pine barren flatsedge |
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Habit | Herbs, perennial, coarse; rhizomes (seldom collected) indurate, oblique, 5–12 mm wide, with fibrous brown floral scales, 1–5 cm. | Herbs, perennial, cespitose, shortly rhizomatous. |
Culms | 1–3, trigonous to roundly trigonous, (30–)40–65(–95) cm × (1–)2–3 mm. |
trigonous, 20–50(–85) cm × 1–2(–4) mm, glabrous. |
Leaves | (1–)5–10, V-shaped, (10–)30–45(–70) cm × 3–7 mm. |
3–6(–10), 10–40(–55) cm × 1.5–4(–5) mm, V- to inversely W-shaped. |
Inflorescence(s) | heads loosely to densely globose-ovoid, (6–)10–12(–20) mm diam.; rays 6–10(–12), 1–8(–12) cm; 2d order rays 1–4, 5–15(–23) mm; bracts (5–)6–8(–10), ascending at 45–60(–75)°, V-shaped, (5–)15–40(–55) cm × (1–)3–7 mm. |
spike 1, densely oblong-ovoid often with small basal branches, 8–16 × 4–12(–16) mm; rays 4–8(–11), 0.5–3.5(–8.5) cm; bracts (3–)4–6(–10), ascending at (30–)45°, flat to broadly V-shaped, (4–)14–30(–55) cm × 1–5 mm, scabridulous along margins only; rachilla deciduous, wings persistent, 0.2–0.3 mm wide. |
Spikelets | (1–)30–50(–65), greenish white, linear to broadly ellipsoid, flattened, 4–6.5 × 1.8–3.2 mm; floral scales (10–)16–20(–26), laterally clear, pale green, off-white, or light brown, medially green or light brown, laterally weakly 1-ribbed, medially 2-ribbed, basally 2-keeled, oblong-lanceolate, (1.2–)1.4–1.6(–1.8) × (0.7–)0.8–1 mm, apex acute, mucronate, distally glabrous or scabridulous. |
40–120, oblong-lanceoloid, subterete, 2.2–4(–4.5) × 0.8–1.6 mm; distal spikelet spreading or ascending; floral scales persistent, 2–5, appressed, brown to stramineous, or fuscous and lustrous, medially greenish and 1(–3)-ribbed, laterally greenish to yellowish white and 3–4-ribbed, oblong to oblong-lanceolate, 1.8–2.5 × 1–1.5 mm, subcoriacous. |
Flowers | stamen 1; anthers ellipsoid, 0.6–0.7 mm, connective apex acute, 0.1–0.2 mm; styles 0.2–0.4 mm; stigmas 0.4–0.6 mm. |
anthers 0.3–0.5 mm; styles 0.5–0.8 mm; stigmas 0.6–0.9 mm. |
Achenes | brown, stipitate, ellipsoid to narrowly ellipsoid, broadly rounded or contracted basally, gradually tapered toward apex, 0.9–1.1 × 0.3–0.4 mm, stipe 0.1 mm, apex acute, surfaces finely reticulate. |
brown, oblong-ellipsoid, 1.2–1.7 × 0.5–0.6 mm, base cuneate, apex subacute, surfaces papillose. |
Cyperus entrerianus |
Cyperus retrorsus |
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Phenology | Fruiting summer. | Fruiting summer (Jun–Aug). |
Habitat | Roadside ditches, marshes | Open woods and thickets in moist to dry, sandy soils |
Elevation | 0–100 m (0–300 ft) | 0–1000 m (0–3300 ft) |
Distribution |
AL; FL; GA; LA; MS; TX; Mexico; South America; Central America (Nicaragua) [Introduced in North America]
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AL; AR; DC; DE; FL; GA; LA; MD; MO; MS; NC; NJ; NY; OK; SC; TN; TX; VA; Mexico (Tamaulipas)
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Discussion | Cyperus entrerianus is a recent introduction in the southern United States (earliest collection from Pensacola County, Florida, Brinker 413, MO in 1941). It has been confused with C. luzulae. The species that Boeckeler had first described 50 years earlier was accepted by G. Kükenthal (1935–1936). Cyperus entrerianus was accepted as a variety of C. luzulae by A. B. Ayers (1946); M. F. Denton (1978b) considered C. entrerianus a synonym of C. luzulae, stating that the features of these two taxa merged so completely throughout their geographic ranges that C. entrerianus could not be given specific status. Cyperus luzulae in the strict sense does not extend northward to North America. Morphologic differences between Cyperus entrerianus and C. luzulae are as follows (G. C. Tucker 1994). Cyperus entrerianus has culms 40–75 cm; inflorescence bracts ascending at 45–60°; primary rays ascending at 45–60(–75)°; 2d order rays present; heads of spikelets loosely globose-ovoid, light greenish white to golden brown; rachilla dark red with stramineous scale scars; and scale apices acute. Cyperus luzulae has culms 20–40 cm; inflorescence bracts approximately horizontal; primary rays ascending at 15–30°; 2d order rays absent; heads of spikelets densely oblong to pyramidal, bright to dull white; rachilla green throughout; and scale apices rounded. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cyperus retrorsus was reported in Indiana (M. L. Horvat 1941); we have been unable to confirm the report. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23. | FNA vol. 23, p. 187. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. luzulae var. entrerianus | Mariscus cylindricus, C. cylindricus, Mariscus retrorsus |
Name authority | Boeckeler: Flora 61: 139. (1878) | Chapman: Bot. Gaz. 3: 17. (1878) |
Web links |