Cyperus floribundus |
Cyperus retrofractus |
|
---|---|---|
Rio Grande sedge |
rough flatsedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose. |
Culms | trigonous, basally tuberous thickened, 15–40 cm × 1–2.5 mm, glabrous. |
with cormlike bases, sharply trigonous, 25–90 cm, glabrous proximally, minutely scabridulous distally. |
Leaves | flat to V-shaped, 10–30 cm × 1–2 mm. |
V-shaped, 14–40 cm × 3.5–8 mm, (pubescent on adaxial side of midrib). |
Inflorescences | spike 1, densely oblong to ellipsoid, 8–36 × 8–20 mm; rays 4–12, 10–20 cm; bracts 3–6, horizontal to ascending at 30°, V-shaped, 3–15 cm × (3–)4–5.8 mm; rachilla deciduous, wings 0.5–0.7 mm wide. |
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. |
Spikelets | (5–)20–35(–60), linear to oblong, quadrangular; 4–12(–21) × 0.7–1.2 mm, base narrowed to 0.4–1 mm; floral scales persistent, 1–3(–5), appressed, laterally whitish to reddish brown, stramineous with reddish spots, medially green, laterally 3–6-ribbed (midrib distinctly scabrid at 30X), narrowly oblong to ovate, 2.6–4.8 × 1.6–2 mm; apex rounded to ± acute, entire, with mucro 0.3–0.5 mm; sterile terminal scale involute, 0.4–0.6 mm wide, uncinate; distal floral scales with cusp 0.6–1.9. |
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. |
Flowers | anthers 0.5–1.3 mm; styles 0.4–0.5 mm; stigmas 0.5–0.9 mm. |
anthers 0.7–1.2 mm; styles 1.5–2 mm; stigmas 2–2.5 mm. |
Achenes | light brown to reddish brown, sessile to slightly stipitate, narrowly ellipsoid, 1.8–2.4 × 0.6–0.8 mm, apex slightly apiculate, surfaces puncticulate. |
brown to brownish black, narrowly oblong, (2.2–)2.5–3 × 0.6–0.7 mm, base cuneate, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus floribundus |
Cyperus retrofractus |
|
Phenology | Fruiting mid summer–early fall (Jul–Sep). | Fruiting summer. |
Habitat | Damp, disturbed soils, croplands | Roadsides, pastures, disturbed sites in sandy or clayey soils |
Elevation | 0–1000 m (0–3300 ft) | 0–300 m (0–1000 ft) |
Distribution |
TX; Mexico |
AL; AR; DC; DE; GA; KY; MO; NC; NJ; OH; PA; SC; TN; VA
|
Discussion | Included previously in Cyperus retroflexus (or its synonym C. uniflorus), C. floribundus has a much narrower geographic range (southern Texas and northeastern Mexico) and differs in features of spikelet morphology (J. R. Carter and S. D. Jones 1997). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. | FNA vol. 23, p. 180. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. uniflorus var. floribundus, C. uniflorus | Scirpus retrofractus, C. dipsaciformis, C. retrofractus var. dipsaciformis, Mariscus retrofractus |
Name authority | (Kükenthal) J. Rich. Carter & S. D. Jones: Rhodora 99: 330. (1998) | (Linnaeus) Torrey: in J. Carey, Carices North. U.S., 519. (1847) |
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