Cyperus parishii |
Cyperus laevigatus |
|
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Parish flatsedge, Parish's flatsedge, Parish's nutgrass |
smooth cyperus, smooth flatsedge, smooth nutgrass |
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Habit | Herbs, annual, cespitose. | Herbs, perennial, rhizomatous. |
Culms | trigonous, 5–25 cm × 1–1.5 mm, glabrous. |
single or close together, trigonous to ± terete, (1–)8–30(–60) cm × (0.3–)0.6–1.5(–2.2) mm, glabrous. |
Leaves | blades present or reduced to sheaths, base of culm covered with reddish sheath 5–25 mm, distally short toothed 1–2 mm, or leaf blades involute, 1–7 cm × 0.3–1(–1.6) mm. |
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Inflorescences | spikes loosely ovoid, 15–25 mm wide; rays 1–6, 2–7 cm; bracts 2–5, 3–20 cm, ascending; rachilla deciduous, winged. |
heads appearing lateral, spikes ± digitate, 5–15 × 5–15 mm; rays absent, sometimes 1, to 2 mm; bracts (1–)2(–3), longer bracts erect, appearing as continuation of culm, shorter bract(s) horizontal or ascending, longer bracts (1–)2–8(–12) cm × 0.5–3 mm, shorter (0.3–)1–4.5 cm × 0.2–1 mm. |
Spikelets | 5–30, linear, flattened, 6–22 × 1.5–2.2 mm; floral scales ± deciduous, (4–)8–12, red, reddish purple, or reddish brown, medially green, elliptic, laterally 2–4-ribbed, 2.3–3.1 × 1.2–2 mm, apex acute to obtuse. |
(1–)2–7(–14), whitish green to reddish, compressed-turgid, ellipsoid to oblong-lanceoloid, 4–7(–12) × (1.6–)2–3(–3.6) mm; floral scales (8–)12–22, off-white, whitish with red speckles, or with single red spot 0.5 mm wide, medially whitish, oblong-laterally ribless or weakly 2-ribbed, medially weakly 1–3-ribbed, obovate to orbiculate, 1.5–2 × (1.3–)1.6–2 mm. |
Flowers | anthers 0.3–0.4 mm; styles 1 mm; stigmas 1.3–1.6 mm. |
anthers (0.5–)0.7–1 mm, connective apex reddish, 0.1–0.2 mm; styles 0.8–1.2 mm; stigmas 0.7–1 mm. |
Achenes | brown to dark purplish brown, broadly ellipsoid, 1–1.3 × 0.6–0.9 mm, surfaces puncticulate. |
gray, glossy, oblong-ellipsoid to ovoid, (1.2–)1.3–1.5(–1.8) × (0.7–)0.8–1(–1.2) mm, base cuneate to stipelike, apex apiculate, surfaces finely reticulate to papillate. |
Cyperus parishii |
Cyperus laevigatus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, desert washes, arroyos, roadsides | Alkaline grasslands, hotsprings, ditches, brackish marshes |
Elevation | 0 800 m (0 2600 ft) | 0–1000 m (0–3300 ft) |
Distribution |
AZ; CA; NM
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AZ; CA; NC; TX; Mexico; South America; West Indies; Europe; Asia; Africa
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Discussion | Cyperus laevigatus is one of only two species of subg. Juncellus in the New World. It can be distinguished from all other New World species of Cyperus by its two stigmas and disclike, strongly flattened achene, which is borne with its face toward the rachilla. Species of subg. Pycreus, especially C. niger, have been misidentified as C. laevigatus, probably because of the dark, shiny spikelets. All species of subg. Pycreus have biconvex achenes like C. laevigatus; in species of subg. Pycreus the achene is attached with an edge toward the rachilla; in C. laevigatus the achene faces the rachilla. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 170. | FNA vol. 23, p. 164. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Juncellus |
Sibling taxa | ||
Synonyms | C. congestus var. parishii | Acorellus laevigatus, Chlorocyperus laevigatus, Juncellus laevigatus, Pycreus laevigatus |
Name authority | Britton ex Parish: Bull. S. Calif. Acad. Sci. 3: 52, plate 3. (1904) | Linnaeus: Mant. Pl. 2: 179. (1771) |
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