Cyperus hermaphroditus |
Cyperus onerosus |
|
---|---|---|
hermaphrodite flatsedge |
plains flatsedge |
|
Habit | Herbs, perennial, rhizomatous. | Herbs, perennial, cespitose, rhizomatous; base cormlike; rhizomes scaly, 12 cm × 2 mm. |
Culms | trigonous, (10–)30–80(–140) cm × (0.4–)1–3(–5) mm, glabrous. |
trigonous, 20–55 cm × 1.2–11.8 mm, glabrous. |
Leaves | V-shaped or flanged V-shaped, (5–)15–70(–90) cm × (2–)4–10(–13) mm, glabrous. |
V-shaped, 12–30 cm × 2–3 mm. |
Inflorescences | 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. |
heads digitate, 12–20 mm diam.; rays 7–12, 1–13 cm; 2d order rays 1–3 cm (sometimes absent); bracts 3–5, longest ± erect, V-shaped, 5–12(–18) cm × 2–3 mm. |
Spikelets | (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. |
(8–)20–30, linear-lanceoloid, compressed, 5–10(–14) × 1.4–1.7 mm; floral scales (8–)16–26, laterally brown to reddish brown, medially green, laterally 1-ribbed, medially 3-ribbed, broadly elliptic, 2–2.5 × 1.2–1.6 mm, apex with slightly excurved cusp 0.2–0.3 mm. |
Flowers | anthers (0.4–)0.6–1 mm; styles 0.4–1.6 mm; stigmas 1–1.5 mm. |
stamens 3; anthers 1 mm, connective apex reddish, subulate, 0.1 mm; styles 1–1.5 mm; stigmas 1.5 mm. |
Achenes | 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. |
white to light brown, sessile, ellipsoid, 0.7–0.8 × 0.25–0.35 mm, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus hermaphroditus |
Cyperus onerosus |
|
Phenology | Fruiting summer–fall. | Fruiting early summer (May–Jun). |
Habitat | Arroyos | Permanent pools and wet swales between sand dunes |
Elevation | 500–1200 m (1600–3900 ft) | 1200 m (3900 ft) |
Distribution |
AZ; TX; Mexico; South America; West Indies |
TX |
Discussion | 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.) |
Of conservation concern. Cyperus onerosus is apparently restricted to Andrews and Winkler counties in Texas. This interesting endemic is most similar to Cyperus dentatus; it lacks tubers and apparently is not proliferous. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 186. | FNA vol. 23, p. 151. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | Carex hermaphrodita, Mariscus hermaphroditus, Mariscus jacquinii | |
Name authority | (Jacquin) Standley: Contr. U.S. Natl. Herb. 18: 88. (1916) | M. C. Johnston: SouthW. Naturalist 9: 308. (1964) |
Web links |