Cyperus retrofractus |
Cyperus distans |
|
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rough flatsedge |
Piedmont flatsedge |
|
Habit | Herbs, perennial, cespitose. | Herbs, perennial, rhizomatous. |
Culms | with cormlike bases, sharply trigonous, 25–90 cm, glabrous proximally, minutely scabridulous distally. |
single or close together, trigonous, (10–)40–80(–120) cm × 1.2–2.5(–5) mm, glabrous. |
Leaves | V-shaped, 14–40 cm × 3.5–8 mm, (pubescent on adaxial side of midrib). |
2–5, pleated, (10–)20–50(–90) cm × 2–5(–10) mm. |
Inflorescences | spikes loose, obtrulloid to obdeltoid (broadest near apex, nearly as long as wide), 20–28(–34) × (12–)15–30 mm; rays 4–13, (1–)4–24 cm (longest ray shorter than bracts), glabrous; bracts 3–12, ascending at 30–45°, flat, 3–25 cm × 3–7 mm; rachilla persistent, wings 0.4–0.6 mm wide, covering 3/4 of mature achene. |
spikes 1–4(–7), loose, broadly ovoid to ovoid-pyramidal, 25–35 × 25–35 mm; rays (4–)5–6(–8), (1–)3–8(–16) cm, glabrous; 2d order rays (0–)1–5, 5–15(–50) mm; bracts 4–7, ascending at 30–45°, pleated, (5–)20–40(–60) × (2–)3–8(–11) mm; 2d order bracts 1–4 per ray, 5–10(–30) × 0.5–1 mm, scabridulous; rachilla persistent, wingless (or very narrowly winged, not clasping achene). |
Spikelets | 30–50, proximal one reflexed, distal ones divaricate, linear-lanceoloid, ± terete, (6.5–) 8–10(–17) × 0.5–0.7 mm; floral scales persistent, 3–6(–8), appressed, stramineous (suffused with reddish purple), 4–5-ribbed laterally, ovate-lanceolate, (4–)4.4–4.9(–5.4) × 1.3–1.5 mm; terminal scale not spinose, apex straight, excurved mucronate, or cuspidate. |
(10–)20–35(–45), seemingly flattened proximally from spreading floral scales, becoming terete apically, linear, (10–)13–18(–25) × 1.2–1.5(–1.6) mm; floral scales deciduous, (10–)12–20(–25), laterally light reddish brown to dark red, medially greenish, laterally ribless, medially 3–5-ribbed, oblong-ovate, 1.7–2(–2.4) × 0.9–1.2 mm, apex obtuse, barely reaching next scale, apex entire, emarginate, mucro at most 0.3 mm. |
Flowers | anthers 0.7–1.2 mm; styles 1.5–2 mm; stigmas 2–2.5 mm. |
anthers 0.4–0.5 mm; styles 0.3–0.6 mm; stigmas 1–1.8(–2) mm. |
Achenes | brown to brownish black, narrowly oblong, (2.2–)2.5–3 × 0.6–0.7 mm, base cuneate, apex obtuse, apiculate, surfaces puncticulate. |
dark brown, narrowly oblong, (1.3–)1.4–1.6(–1.7) × (0.3–)0.4–0.5 mm, base cuneate to ± stipelike, apex acute, not apiculate, surfaces papillose. |
Cyperus retrofractus |
Cyperus distans |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Roadsides, pastures, disturbed sites in sandy or clayey soils | Marshes |
Elevation | 0–300 m (0–1000 ft) | 0 m (0 ft) |
Distribution |
AL; AR; DC; DE; GA; KY; MO; NC; NJ; OH; PA; SC; TN; VA
|
FL; NC; Mexico; South America; West Indies (Dominican Republic south through the Lesser Antilles); Asia; Africa |
Discussion | For information concerning nomenclature of Cyperus retrofractus, see J. R. Carter and C. E. Jarvis (1986). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 23, p. 180. | FNA vol. 23. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Scirpus retrofractus, C. dipsaciformis, C. retrofractus var. dipsaciformis, Mariscus retrofractus | C. elatus |
Name authority | (Linnaeus) Torrey: in J. Carey, Carices North. U.S., 519. (1847) | Linnaeus f.: Suppl. Pl., 103. (1782) |
Web links |