Cyperus parishii |
Cyperus cephalanthus |
|
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Parish flatsedge, Parish's flatsedge, Parish's nutgrass |
buttonbush flatsedge |
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Habit | Herbs, annual, cespitose. | Herbs, perennial, rhizomatous. |
Culms | trigonous, 5–25 cm × 1–1.5 mm, glabrous. |
trigonous, 40–70(–100) cm × 2–3 mm, scabrid or hirtellate, either immediately proximal to apex or over distal 1/2 of culm. |
Leaves | flat, 30–80 cm × 4–10 mm, scabrid on margins, ribs on abaxial surface. |
|
Inflorescences | spikes loosely ovoid, 15–25 mm wide; rays 1–6, 2–7 cm; bracts 2–5, 3–20 cm, ascending; rachilla deciduous, winged. |
spikes ovoid, 12–20 × 13–18 mm; rays 3–6, 4–10(–16) cm, glabrous; bracts 3–5, ± horizontal to reflexed, 3–12(–36) cm × 0.4–3(–5) mm, scabrid like leaves; rachilla deciduous, essentially wingless or wings inconspicuous, hyaline, 0.1(–0.2) mm wide. |
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. |
25–50(–80), oblong, quadrangular-compressed, 5–10 × 2.5–3.5 mm; floral scales deciduous, 4–10(–14), marginally clear, laterally brownish to clear distally, or light brown or reddish brown, blunt, laterally 3(–4)-ribbed, ovate-lanceolate, 2.5–3 × (1.2–)1.4–2 mm, often erose apically, apex acute to obtuse, entire or emarginate. |
Flowers | anthers 0.3–0.4 mm; styles 1 mm; stigmas 1.3–1.6 mm. |
anthers 0.4–0.6 mm; styles 0.8–1.2 mm; stigmas 2 mm. |
Achenes | brown to dark purplish brown, broadly ellipsoid, 1–1.3 × 0.6–0.9 mm, surfaces puncticulate. |
brown to reddish brown, ± stipitate, ellipsoid, 1.2 × 0.5–0.6 mm, apex obtuse, scarcely to distinctly apiculate, surfaces puncticulate. |
Cyperus parishii |
Cyperus cephalanthus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, desert washes, arroyos, roadsides | Wet prairies |
Elevation | 0 800 m (0 2600 ft) | 0–50 m (0–200 ft) |
Distribution |
AZ; CA; NM
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LA; OK; TX; South America (Argentina, Brazil, Paraguay, Uruguay) |
Discussion | The combination of spreading floral scales and scabrid culms separates this rather uncommon species from any others occurring in its range. The scarcity of Cyperus cephalanthus in the United States and its disjunct distribution suggest it might be naturalized rather than native. It was collected early in the nineteenth century in Louisiana, and the amphitropical distribution is not without parallel in the genus (cf. 12. C. eragrostis). Cyperus cephalanthus has been treated as a variety of the widespread, polymorphic South American C. laetus (G. Kükenthal 1935–1936). Recognition of C. cephalanthus as a species follows recent American floristic practice. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 170. | FNA vol. 23. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. congestus var. parishii | C. laetus var. cephalanthus |
Name authority | Britton ex Parish: Bull. S. Calif. Acad. Sci. 3: 52, plate 3. (1904) | Torrey & Hooker: Ann. Lyceum Nat. Hist. New York. 3: 431. (1836) |
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