Cyperus floribundus |
Cyperus plukenetii |
|
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Rio Grande sedge |
Plukenet's flatsedge, Plukenet's sedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose. |
Culms | trigonous, basally tuberous thickened, 15–40 cm × 1–2.5 mm, glabrous. |
basally cormlike, obtusely trigonous to subterete, 25–100 cm × 2–4 mm, densely minutely scabridulous. |
Leaves | flat to V-shaped, 10–30 cm × 1–2 mm. |
inversely W-shaped, 20–70 cm × 4–7 mm, adaxial surface densely hirtellous. |
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 turbinate, 10–12 × 6–9 mm, ± as long as wide; rays 6–12, 1–30 cm (longest bract equaling or shorter than longest ray), harshly scabrid; bracts 3–10, horizontal to ascending at 30°, inversely W-shaped, 6–27 cm × 3–6 mm; rachilla persistent, wings hyaline, 0.5 mm wide, covering 1/2 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. |
30–60, proximal spikelets reflexed nearly parallel to ray, distal ones spreading, linear, ± terete, 6–8 × 1–1.4 mm; floral scales persistent, 1(–2), appressed, stramineous, often suffused with reddish purple, laterally 4–6-ribbed, ovate-lanceolate, 4–4.5 × 1.4–1.6 mm, apex straight, excurved mucronate or cuspidate; terminal scale spinose. |
Flowers | anthers 0.5–1.3 mm; styles 0.4–0.5 mm; stigmas 0.5–0.9 mm. |
anthers 0.5–1 mm; styles 1.5–2 mm; stigmas 2 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. |
dark brown, narrowly oblong, (2.4–)2.7–2.9(–3.2) × 0.7–0.8 mm, base cuneate, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus floribundus |
Cyperus plukenetii |
|
Phenology | Fruiting mid summer–early fall (Jul–Sep). | Fruiting summer (Jul–Aug). |
Habitat | Damp, disturbed soils, croplands | Dry sand hills, xeric upland woods |
Elevation | 0–1000 m (0–3300 ft) | 0–200 m (0–700 ft) |
Distribution |
TX; Mexico |
AL; AR; DE; FL; GA; KY; LA; MD; MO; MS; NC; NJ; OK; SC; TN; TX; 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.) |
Cyperus plukenetii is distinguished by its tight, burlike spikes, few-flowered spikelets, and densely pubescent culms, leaves, and rays. (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 | |
Name authority | (Kükenthal) J. Rich. Carter & S. D. Jones: Rhodora 99: 330. (1998) | Fernald: Rhodora 47: 110, plate 877. (1945) |
Web links |