Cyperus haspan |
Cyperus retroflexus |
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haspan flatsedge |
one-flower flatsedge |
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Habit | Herbs, perennial, cespitose, shortly rhizomatous. | Herbs, perennial, cespitose, rhizomatous. |
Culms | trigonous, (2–)25–60(–100) cm × 1–4 mm, soft (flattened in drying), glabrous. |
trigonous, basally tuberous-thickened, (5–)15–40(–80) cm × 1–2.5 mm, glabrous. |
Leaves | usually reduced to sheaths, occasionally with blades, flat to V-shaped, (3–)10–30 cm × (1–)2.5–5 mm. |
flat to V-shaped, (5–)10–30(–60) cm × (0.5–)1–3(–4) mm. |
Inflorescences | heads loosely digitate; rays (5–)10–12(–15), 1–15(–20) cm; 2d order rays usually present, (1–)6–12(–25) mm; 3d order rays sometimes present, 1–6 mm; bracts 2(–3), horizontal to ascending at 30–60°, longer (3–)6–18 cm × 2–4 mm, shorter (0.5–)2.5–6.5 cm × 1–2(–3) mm. |
spike 1, loosely to densely ovoid to cylindric, 8–36 × 8–20 mm; rays 3–6(–9), (5–)10–32 cm; bracts 3–6, horizontal to ascending at 30°, V-shaped, (1–)3–15(–30) cm × 0.5–4.5 mm; rachilla deciduous, wings 0.5–0.7 mm wide. |
Spikelets | 1–15, linear-lanceoloid, ± compressed-quadrangular, 3–18 × 1–1.6 mm; floral scales 10–20(–40), laterally reddish to greenish brown, dull, often clear-edged, medially greenish, laterally 1-ribbed, medially 1-ribbed, oblong to obovate, 1–1.5(–1.9) × 0.8–1 mm, apex mucronate, glabrous except for cluster of crystalline prickles at apex. |
(5–)20–35(–65), linear to oblong (without narrowed basal portion), quadrangular; (2.2–)4–10(–18) × 0.7–1.1 mm; floral scales persistent, 1–5, appressed, pale greenish white laterally, stramineous with reddish dots, or deep red, greenish or light brown medially, 3–6-ribbed laterally, narrowly ovate to oblong-elliptic, 2.6–3.9 × 1.6–2 mm, apex rounded to ± acute, entire, mucronulate; distal scale with glabrous midrib and mucro 0.1–0.3(–0.5) mm; sterile terminal scale of spikelet only 0.4–0.6 mm wide, involute, frequently uncinate. |
Flowers | stamens 3; anthers 0.3–0.5 mm; styles 0.4–0.9 mm; stigmas 0.5–0.8(–1.3) mm. |
anthers (0.3–)0.4–0.6 mm; styles 0.4–0.5 mm; stigmas 0.5–0.9 mm. |
Achenes | white or reddish brown, stipitate, globose to obovoid or ellipsoid, 0.5–0.6(–0.7) × 0.3–0.4(–0.5) mm, base nearly cuneate, stipe 0.1 × 0.1–0.2 mm, apex obtuse to acute, apiculate or entire, surfaces granular to papillose. |
light brown to reddish brown, sessile or slightly stipitate, ellipsoid, (1.8–)2–2.4 × 0.6–0.8(–0.9) mm, apex slightly apiculate, surfaces puncticulate. |
Cyperus haspan |
Cyperus retroflexus |
|
Phenology | Fruiting summer. | Fruiting mid summer–early fall (Jul–Sep). |
Habitat | Swales between dunes, marshes, pond shores | Damp, disturbed soils, croplands |
Elevation | 0–200 m [0–700 ft] | 0–1000 m [0–3300 ft] |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX; VA; Mexico; Central America; South America; Asia; Africa; Australia
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AL; AR; AZ; MO; MS; NM; OK; TX; Mexico
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Discussion | Cyperus retroflexus is distinguished from other species of Cyperus with deciduous spikelets by the involute, sterile terminal scale of the spikelet. In plants with cuspidate scales, the terminal scale is usually somewhat recurved, giving the appearance of a hook at the end of the spikelet. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 151. | FNA vol. 23. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. autumnalis, C. haspan subsp. juncoides, C. haspan var. americanus, C. juncoides | C. uniflorus var. floribundus, C. uniflorus var. retroflexus, Mariscus uniflorus |
Name authority | Linnaeus: Sp. Pl. 1: 45. (1753) | Buckley: Proc. Acad. Nat. Sci. Philadelphia. 14: 9. (1862) |
Web links |