Cyperus floribundus |
Cyperus refractus |
|
---|---|---|
Rio Grande sedge |
reflexed flatsedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose, with inconspicuous, short rhizomes scarcely visible between culm bases. |
Culms | trigonous, basally tuberous thickened, 15–40 cm × 1–2.5 mm, glabrous. |
basally cormlike, trigonous, 30–100 cm × 2–4 mm, glabrous. |
Leaves | flat to V-shaped, 10–30 cm × 1–2 mm. |
V-shaped to flat, 20–70 cm × 3–8 mm, adaxial surface, margins minutely scabridulous. |
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, broadly ellipsoid to ovoid, 4–7 × 2–6 cm; rays 6–13(–16), 4–25 cm, glabrous; rachis 1.5–3 cm; bracts 3–6, horizontal to ascending at 30°, flat, 5–35 cm × 2.5–6 mm; rachilla persistent, wings 0.4–0.5 mm wide. |
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. |
(13–)20–60(–74), linear, ± terete, (11–)13–25(–28) × 1.2–1.5 mm; distal spikelets spreading or ascending; floral scales persistent, (2–)3–6, stramineous, red-purple striate, laterally 3–5-ribbed, ovate-lanceolate, 4.5–5.3 × 1.2–1.5 mm. |
Flowers | anthers 0.5–1.3 mm; styles 0.4–0.5 mm; stigmas 0.5–0.9 mm. |
anthers 1–1.5 mm; styles 1.5 mm; stigmas 1.5 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 purplish brown, oblong-linear (5–6 times long as wide), 2.6–3 × 0.5–0.6 mm, base cuneate, apex obtuse, surfaces puncticulate. |
Cyperus floribundus |
Cyperus refractus |
|
Phenology | Fruiting mid summer–early fall (Jul–Sep). | Fruiting summer (Jul–Aug). |
Habitat | Damp, disturbed soils, croplands | Sandy riverbanks, gravelly roadsides, pastures, disturbed places |
Elevation | 0–1000 m (0–3300 ft) | 20–300 m (100–1000 ft) |
Distribution |
TX; Mexico |
AL; AR; DC; GA; MD; MO; NC; PA; SC; TN; VA; WV |
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.) |
Cyperus refractus is often mistaken for C. strigosus, which has shorter anthers (0.4–0.5 mm) and spreading, ± deciduous floral scales. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23. | FNA vol. 23, p. 182. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. uniflorus var. floribundus, C. uniflorus | |
Name authority | (Kükenthal) J. Rich. Carter & S. D. Jones: Rhodora 99: 330. (1998) | Engelmann ex Boeckeler: Linnaea 36: 369. 1870, based on Cyperus refrofractus Engelmann ex Steudel, Syn. Pl. Glumac. 2: 47. 1855, not (Linnaeus) Torrey (1848) |
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