Cyperus oxylepis |
Cyperus diandrus |
|
---|---|---|
sharpscale flatsedge |
umbrella flat sedge |
|
Habit | Herbs, perennial, cespitose, coarse, (culms, leaves, bracts, and rays viscid). | Herbs, annual, cespitose, with fibrous roots. |
Culms | roundly trigonous, 10–50 cm × 0.9–2.4 mm. |
trigonous, 4–25(–35) cm, glabrous. |
Leaves | adaxial face concave, becoming flat to trigonous apically, 10–46 cm × 1.5–4 mm, margins involute. |
flat, 5–20 cm × 1.5–3 mm. |
Inflorescences | spikes ovoid, 1–5.5 cm wide; rays usually 3–6, 0.5–5 cm, glabrous; sometimes absent in small plants; if absent, inflorescence a congested head of spikelets 1–3.5 cm diam.; 2d order rays 0–3, 1–3 cm; bracts 3–5, vertical to ascending at 45°, 2.5–25 cm × 1.2–4 mm, margins involute; 2d order bracts 0–2, 5–20 mm; rachilla persistent, wingless. |
heads ± digitate, 12–22 mm diam.; rays 3–6, 1–6 cm; bracts 1–4, ± horizontal, flat, 1.5–15 cm × 1.5–3 mm. |
Spikelets | 5–24, greenish yellow to golden brown, oblong to linear-lanceoloid, quadrangular, strongly compressed, 7–20(–30) × 2.5–4(–6) mm; floral scales 10–20(–40), spreading, pale green to stramineous, laterally 2–3-ribbed, ovate-lanceolate, 3.1–4 × 1.5–2.4 mm, apex with mucro 0.2–0.8 mm. |
6–12, oblong-lanceoloid, compressed, 5–10 × 2.8–3.2 mm; floral scales 8–28, closely imbricate, stramineous to light brown or clear (marginal band bright red, spikelet thus appearing dark margined), laterally ribless, oblong to ovate, 2.5–3 × 1.6–1.9 mm. |
Flowers | anthers 0.6–0.8 mm; styles 0.8–1.6 mm; stigmas 1–1.4 mm. |
stamens 2(–3); anthers 0.3 mm, connective apex reddish, subulate, 0.1–0.2 mm; styles 0.3–0.5 mm; stigmas 2.2–3.1 mm. |
Achenes | light to dark brown, rarely somewhat reddish, stipitate, ellipsoid, 2–2.4 × 0.5–0.8 mm, base cuneate, stipe whitish, spongy, 0.2–0.3 × 0.2–0.4 mm, apex acute, persistent style forming beak 0.5–1.2 mm, surfaces glabrous or finely papillose. |
brown, network of ridges forming isodiametric or square cells, sessile or stipitate, obovoid to ovoid, 1–1.2 × 0.5–0.6 mm, stipe, if present, 0.1 mm, apex obtuse, apiculate, surfaces minutely punctate. |
Cyperus oxylepis |
Cyperus diandrus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Ditches and disturbed places in marshes, often in saline soil | Emergent shorelines, in sandy, peaty, or slightly brackish areas (though seldom where disturbed) |
Elevation | 0–100 m (0–300 ft) | 0–600 m (0–2000 ft) |
Distribution |
AR; FL; GA; LA; MS; SC; TX; Mexico; South America [Introduced in North America]
|
CT; DE; IA; IL; IN; MA; MD; ME; MI; MN; MO; NE; NH; NJ; NY; PA; RI; VA; VT; NB; NS; ON; QC
|
Discussion | Cyperus oxylepis is easily recognized by its sticky leaves, culms, and bracts (in living plants), involute leaves,and golden brown spikelets. The ovate-lanceolate floral scales and the ellipsoid, brownish achene with a persistent beak distinguish C. oxylepis from other species with deciduous floral scales. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 23, p. 171. | FNA vol. 23, p. 161. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycreus |
Sibling taxa | ||
Synonyms | Pycreus diander | |
Name authority | Nees ex Steudel: Syn. Pl. Glumac. 2: 25. (1855) | Torrey: Cat. Pl. New York, 90. (1819) |
Web links |
|