Cyperus virens |
Cyperus retrorsus |
|
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green flatsedge |
pine barren flatsedge |
|
Habit | Herbs, perennial, cespitose; rhizomes 0.5–2 cm, often absent. | Herbs, perennial, cespitose, shortly rhizomatous. |
Culms | trigonous, (20–)60–70(–100) cm × 2.4–6.9 mm, scabrid on angles. |
trigonous, 20–50(–85) cm × 1–2(–4) mm, glabrous. |
Leaves | 4–12, flat to V-shaped, with readily visible cross ribs especially on abaxial surface, 20–50 cm × 3–14 mm. |
3–6(–10), 10–40(–55) cm × 1.5–4(–5) mm, V- to inversely W-shaped. |
Inflorescence(s) | heads digitate to hemispheric, 1–3.5 cm diam.; rays 6–12, 1–9(–14) cm; 2d order rays often present, (0.5–)1–3 cm; 3d order rays occasionally present, 5–12 mm; bracts 4–8, horizontal to ascending at 30°, with prominent cross ribs,V-shaped, (1.5–)3–50(–75) cm × 0.5–13 mm; 2d order bracts 3–10 × 1–2 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 | 10–40(–50), oblong to linear-lanceoloid, 5–18 × 2–3.2 mm; floral scales 10–40, pale grayish brown, or greenish, proximally greenish or brownish, oblanceolate, 2-keeled, weakly to distinctly 1-ribbed, proximal half 2-ribbed, (1.3–)1.5–2(–2.4) × 0.9–1.4 mm, apex acute (sometimes mucronulate), apically glabrous, occasionally 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 | stamens 1–2; anthers 0.8–1.4 mm; styles 0.8–1 mm; stigmas 0.6–0.8 mm. |
anthers 0.3–0.5 mm; styles 0.5–0.8 mm; stigmas 0.6–0.9 mm. |
Achenes | brown, slightly to distinctly stipitate, ellipsoid (2.7–4.1 times as long as wide), (0.9–)1.2–1.5 × 0.3–0.4 mm, apical beak 0.1–0.5 mm, surfaces glabrous. |
brown, oblong-ellipsoid, 1.2–1.7 × 0.5–0.6 mm, base cuneate, apex subacute, surfaces papillose. |
Cyperus virens |
Cyperus retrorsus |
|
Phenology | Fruiting spring–fall. | Fruiting summer (Jun–Aug). |
Habitat | Wet pastures, marshes, roadside ditches | Open woods and thickets in moist to dry, sandy soils |
Elevation | 0–1000 m (0–3300 ft) | |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX; Mexico; Central America; South America
|
AL; AR; DC; DE; FL; GA; LA; MD; MO; MS; NC; NJ; NY; OK; SC; TN; TX; VA; Mexico (Tamaulipas)
|
Discussion | Cyperus virens was found as waif in California in the 1800s (M. F. Denton 1978b; G. C. Tucker 1993b). Cyperus virens is readily distinguished from other species of subg. Pycnostachys by its trigonous culms, scabrid angles, and leaves and inflorescence bracts conspicuously septate by numerous cross ribs between the main ribs. (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, p. 153. | FNA vol. 23, p. 187. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | Mariscus cylindricus, C. cylindricus, Mariscus retrorsus | |
Name authority | Michaux: Fl. Bor.-Amer. 1: 28. (1803) | Chapman: Bot. Gaz. 3: 17. (1878) |
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