Cyperus laevigatus

Linnaeus
Mant. Pl. 2: 179. 1771.
Illustrated
Synonyms: Acorellus laevigatus (Linnaeus) Palla Chlorocyperus laevigatus (Linnaeus) Palla Juncellus laevigatus (Linnaeus) C. B. Clarke Pycreus laevigatus (Linnaeus) Nees
Treatment appears in FNA Volume 23. Treatment on page 164. Mentioned on page 142, 162.

Herbs, perennial, rhizomatous. Culms 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. Inflorescences: 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 (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 (0.5–)0.7–1 mm, connective apex reddish, 0.1–0.2 mm; styles 0.8–1.2 mm; stigmas 0.7–1 mm. Achenes 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.


Phenology: Fruiting summer.
Habitat: Alkaline grasslands, hotsprings, ditches, brackish marshes
Elevation: 0–1000 m

Distribution

V23 262-distribution-map.jpg

Ariz., Calif., N.C., Tex., Mexico, West Indies, South America, Europe, Asia, Africa.

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.

Selected References

None.

Lower Taxa

None.

... more about "Cyperus laevigatus"
Gordon C. Tucker* +, Brian G. Marcks* +  and J. Richard Carter * +
Linnaeus +
Cyperus sect. Juncellus +
Ariz. +, Calif. +, N.C. +, Tex. +, Mexico +, West Indies +, South America +, Europe +, Asia +  and Africa. +
0–1000 m +
Alkaline grasslands, hotsprings, ditches, brackish marshes +
Fruiting summer. +
Illustrated +
Acorellus laevigatus +, Chlorocyperus laevigatus +, Juncellus laevigatus +  and Pycreus laevigatus +
Cyperus laevigatus +
Cyperus subg. Juncellus +
species +