Cyperus reflexus
Cyperus cephalanthus
bentawn flatsedge
buttonbush flatsedge
roundly trigonous to terete, 30–80 cm × 1–1.6 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.
1–6, 10–40 cm, glabrous or essentially so.
flat, 30–80 cm × 4–10 mm, scabrid on margins, ribs on abaxial surface.
heads ovoid to pyramidal, 9–15 mm diam.;
rays 0 or 3–6, 0.5–4 cm, glabrous;
bracts 3–4, longest erect, appearing as continuation of culm, others horizontal to ascending, 4–17 cm × 1.5–4 mm.
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.
25–60, reddish with contrasting yellowish or greenish edges, oblong-lanceoloid, strongly compressed, 5–6(–15) × 1.5–2.5 mm;
floral scales 10–22, laterally reddish, medially yellowish green, 2-keeled, laterally strongly 1-ribbed on each side, proximally grooved, ovate-elliptic, 1.4–2.2 × 0.8–1.5 mm, apex acute, apically scabridulous (sometimes glabrous).
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.
stamen 1;
anthers 0.6–1 mm;
styles 0.3–0.5 mm;
stigmas 0.3–0.6 mm.
anthers 0.4–0.6 mm;
styles 0.8–1.2 mm;
stigmas 2 mm.
reddish brown, stipitate, ovoid-ellipsoid, 0.8–0.9 × 0.3–0.4 mm, stipe 0.1–0.2 mm, apex acute to acuminate, surfaces reticulate or subtly rugulose.
brown to reddish brown, ± stipitate, ellipsoid, 1.2 × 0.5–0.6 mm, apex obtuse, scarcely to distinctly apiculate, surfaces puncticulate.
Cyperus reflexus
Cyperus cephalanthus
Cyperus reflexus is recognized by its reddish scales with contrasting greenish or yellow keels and by the laterally 1ribbed scales. The lateral rib is most often situated where the reddish and yellowish parts of the scale meet. Two varieties of C. reflexus, var. reflexus and var. fraternus, have been recognized (M. F. Denton 1978b). Both varieties were noted as intermingled in the North American and South American segments of the widely disjunct range of C. reflexus. Such variation does not seem significant at the varietal level (see G. C. Tucker 1994; G. C. Tucker and R. McVaugh 1993).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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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