Cyperus niger |
Cyperus hermaphroditus |
|
---|---|---|
black flatsedge, brown cyperus |
hermaphrodite flatsedge |
|
Habit | Herbs, perennial, rhizomatous. | Herbs, perennial, rhizomatous. |
Culms | solitary or close together, trigonous, 5–40(–95) cm, glabrous. |
trigonous, (10–)30–80(–140) cm × (0.4–)1–3(–5) mm, glabrous. |
Leaves | (2–)3–7, broadly V-shaped, 3–20(–30) cm × 1.5–3 mm. |
V-shaped or flanged V-shaped, (5–)15–70(–90) cm × (2–)4–10(–13) mm, glabrous. |
Inflorescences | spikes loosely to densely ovoid to hemispheric, 7–16 mm diam.; rachis 1–2 mm, or absent; rays 1–2, 3–45 mm; if rays absent, inflorescence sessile, dense, 6–20 mm diam; bracts 2–3, horizontal to reflexed downward, broadly V-shaped, 1–15 cm × 1–3 mm. |
spikes 1(–5), rather densely ovoid or oblong-cylindric, (10–)25–45(–62) × 7–22 mm, 11–21 spikelets per 5 mm of rachis; rays (3–)5–10(–17), (1–)5–12(–24) cm; bracts (2–)4–8, ascending at 30–45°, V- or inversely W-shaped, (2–)8–40(–65) cm × (1–)2–8 mm; rachilla deciduous, wings 0.4–0.5 mm wide. |
Spikelets | (3–)5–25(–60), linear to oblong-linear, (3–)5–9 × 1.8–2.3 mm; floral scales 4–18, closely imbricate, chestnut brown, black, or brown, medially green or greenish brown, laterally ribless, medially 2(–3)-ribbed, distinctly 2-keeled basally, ovate to orbiculate, 1.5–2.1 × 1.4–2.2 mm, apex obtuse. |
(10–)50–150, oblong to linear, quadrangular, (3–)4–8(–18) × (0.8–)1–1.2(–1.6) mm; distal spikelet spreading or ascending; floral scales (1–) 3–8, pale greenish white to golden brown, deep brown, or reddish brown, medially usually green, weakly to strongly 3(–4)-ribbed laterally, 1–3-ribbed medially, ovate to elliptic, (2–)2.6–3.2(–4) × 1.2–2 mm, apex obtuse. |
Flowers | stamens 2; anthers 0.6–0.8 mm, connectives not prolonged; styles 0.4–0.6 mm; stigmas 0.7–2.1 mm. |
anthers (0.4–)0.6–1 mm; styles 0.4–1.6 mm; stigmas 1–1.5 mm. |
Achenes | brown, ellipsoid, 1.2–1.4 × 0.6–0.8 mm, network of ridges forming isodiametric or square cells, slightly stipitate, apex apiculate, surfaces minutely punctate. |
brown or reddish brown, sessile or nearly so, ellipsoid, 1.4–1.8(–2) × 0.6–0.8(–1) mm, apex acute to obtuse, slightly apiculate, surfaces puncticulate. |
Cyperus niger |
Cyperus hermaphroditus |
|
Phenology | Fruiting summer. | Fruiting summer–fall. |
Habitat | Swamps, ditches, wet pastures, seeps in montane forests | Arroyos |
Elevation | 0–1200 m (0–3900 ft) | 500–1200 m (1600–3900 ft) |
Distribution |
AZ; CA; NM; OK; TX; Mexico; Central America; South America
|
AZ; TX; Mexico; South America; West Indies |
Discussion | Six varieties (Cyperus niger var. niger, var. castaneus, var. robustus, var. lorentizianus, var. intricate-ramosus, and var. pseudo-elegantulus) were recognized by G. Kükenthal (1935–1936). Based on field observations and measurements of hundreds of collections from Mexico, where the species is most plentiful, it does not seem possible to recognize any of the infraspecific taxa (G. C. Tucker 1983, 1994; G. C. Tucker and R. McVaugh 1993). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
An erroneous report of Cyperus hermaphroditus from Alabama was based on misidentification of C. thyrsiflorus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23. | FNA vol. 23, p. 186. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. diandrus var. castaneus, C. melanostachyus, C. niger var. castaneus | Carex hermaphrodita, Mariscus hermaphroditus, Mariscus jacquinii |
Name authority | Ruiz & Pavón: Fl. Peruv. 1: 47. (1798) | (Jacquin) Standley: Contr. U.S. Natl. Herb. 18: 88. (1916) |
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