Cyperus lanceolatus |
Cyperus virens |
|
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epiphytic flatsedge |
green flatsedge |
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Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose; rhizomes 0.5–2 cm, often absent. |
Culms | trigonous, compressed, 15–75 cm × 0.5–3 mm, glabrous. |
trigonous, (20–)60–70(–100) cm × 2.4–6.9 mm, scabrid on angles. |
Leaves | 1–3, 5–30 cm × 1–2 mm. |
4–12, flat to V-shaped, with readily visible cross ribs especially on abaxial surface, 20–50 cm × 3–14 mm. |
Inflorescences | spikes 1(–2), ovoid, 5–23 × 9–21 mm; rays 2–3(–4), 0–15 mm; if rays absent, head single, compact, sessile, (12–)15–20 mm diam.; bracts 2–3, horizontal to vertical, 2–14 cm × 0.5–3.5 mm. |
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. |
Spikelets | 1–6, oblong-lanceoloid, 5–26 × 2–3 mm; floral scales 12–54, closely imbricate, laterally yellowish brown, medially pale brown, occasionally greenish, laterally 1-ribbed, medially 3-ribbed, distinctly 2-keeled basally, ovate, 1.8–2.6 × 1.4–1.7 mm, apex obtuse. |
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. |
Flowers | stamens 2; anthers 0.4–0.5 mm, connectives not prolonged; styles 0.3–1 mm; stigmas 0.6–0.8(–1) mm. |
stamens 1–2; anthers 0.8–1.4 mm; styles 0.8–1 mm; stigmas 0.6–0.8 mm. |
Achenes | brown, network of ridges forming isodiametric or square cells, stipitate, obovoid to ellipsoid, 1.1–1.3 × (0.5–)0.6 mm, apex acute to broadly rounded, surfaces minutely punctate or finely papillose. |
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. |
Cyperus lanceolatus |
Cyperus virens |
|
Phenology | Fruiting summer. | Fruiting spring–fall. |
Habitat | Marshes | Wet pastures, marshes, roadside ditches |
Elevation | 0–100 m (0–300 ft) | |
Distribution |
AL; FL; GA; LA; TX; Mexico; Central America; South America; Africa
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AL; FL; GA; LA; MS; NC; SC; TX; Mexico; Central America; South America
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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.) |
|
Source | FNA vol. 23, p. 162. | FNA vol. 23, p. 153. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | C. densus, C. humboldtianus, C. lanceolatus var. compositus, Pycreus densus | |
Name authority | Poiret: in J. Lamarck et al., Encycl. 7: 245. (1806) | Michaux: Fl. Bor.-Amer. 1: 28. (1803) |
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