Cyperus reflexus |
Cyperus esculentus |
|||||||||
---|---|---|---|---|---|---|---|---|---|---|
bentawn flatsedge |
nut flatsedge, nut grass, yellow nut sedge, yellow nut-grass |
|||||||||
Habit | Herbs, perennial, cespitose; rhizomes elongate, scaly, 2–3 mm wide. | Herbs, perennial, stoloniferous; stolons soft, spongy, flexible when dried, 2–8(–15) cm, bearing tubers (3–)6–11 mm diam. | ||||||||
Culms | roundly trigonous to terete, 30–80 cm × 1–1.6 mm, glabrous. |
trigonous, 15–60 (–100) cm × 0.6–3.4 mm, glabrous. |
||||||||
Leaves | 1–6, 10–40 cm, glabrous or essentially so. |
3–7, flat to V-shaped or flanged V-shaped, (6–)20–40(–80) cm × 2–4 (–6.5) mm. |
||||||||
Inflorescences | 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 broadly ellipsoid to ovoid or hemispheric, (12–)18–30 × (12–)18–35 mm; rachis 4–17 mm; rays 4–10, (0.3–)2–12 cm; bracts (3–)4–5(–7), ± horizontal to ascending at 45(–75)°, V-shaped to flanged V-shaped, (1.5–)5–30 cm × 0.5–4 mm; rachilla persistent, wings hyaline, 0.3–0.5 mm wide. |
||||||||
Spikelets | 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). |
(3–)10–20(–28), divaricate or ascending, yellowish brown to dark brown, linear to linear-lanceoloid, compressed-quadrangular, (5–)10–20(–55) × (1.2–)1.4–2(–3) mm; floral scales persistent, 6–34, spreading or appressed, ovate-lanceolate, laterally 7–9-ribbed, laterally yellowish brown to dark brown medially brownish, reddish, or greenish, ovate, or ovate-deltate, medially 3-ribbed, 1.8–2.7(–3.4) × (1–)1.5–1.8(–2.4) mm, apex acute or subacute. |
||||||||
Flowers | stamen 1; anthers 0.6–1 mm; styles 0.3–0.5 mm; stigmas 0.3–0.6 mm. |
anthers (1–)1.2–1.5(–2.1) mm; styles (0.7–)1–1.2(–2.2) mm; stigmas (1.2–)1.8–2.3(–4) mm. |
||||||||
Achenes | 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. |
(seldom maturing) brown, sessile, ellipsoid, (1.1–)1.3–1.5(–1.6) × 0.3–0.6(–0.8) mm, apex obtuse, surfaces puncticulate. |
||||||||
Cyperus reflexus |
Cyperus esculentus |
|||||||||
Phenology | Fruiting late spring–fall (May–Oct). | |||||||||
Habitat | Muddy soils or shallow waters | |||||||||
Elevation | 0–200 m (0–700 ft) | |||||||||
Distribution |
FL; LA; OK; TX; Mexico; Central America (Costa Rica) |
AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; BC; NB; ON; QC; nearly worldwide
|
||||||||
Discussion | 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.) |
Varieties 4 (3 in the flora). Cyperus esculentus is a widespread and polymorphic species. Although seven varieties have been recognized (G. Kükenthal (1935–1936), recent studies based primarily on spikelet features provided support for four varieties (P. Schippers et al. 1995). Cyperus esculentus var. esculentus is restricted to the Old World. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||
Key |
|
|||||||||
Source | FNA vol. 23. | FNA vol. 23. | ||||||||
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | C. arenicola, C. fraternus, C. pseudovegetus var. arenicola, C. reflexus var. fraternus | |||||||||
Name authority | Vahl: Enum. Pl. 2: 299. (1805) | Linnaeus: Sp. Pl. 1: 45. (1753) | ||||||||
Web links |
|