Cyperus polystachyos |
Cyperus fugax |
|
---|---|---|
many-spike flatsedge |
withering flatsedge |
|
Habit | Herbs, perennial (annual?), cespitose. | Herbs, annual, cespitose. |
Culms | trigonous or ± terete, (3–)20–45(–70) cm × (0.8–) 1.2–2 mm, glabrous. |
(1–)10–30(–60) together, roundly trigonous proximally, trigonous distally, (0.5–)3–6(–12) cm × (0.2–)0.4–0.8 mm, glabrous. |
Leaves | (2–) 6–10(–16), flat to V-shaped, (2–) 10–30(–60) cm × 1–4 mm. |
V-shaped, (1–)3–5(–10) cm × (0.5–)1–2 mm. |
Inflorescences | spike 1, loosely ovoid to densely turbinate, 12–40 × 10–25 mm; rachis 3–10 mm; rays 1–8(–12), 0.5–3(–6) cm; 2d order rays absent; if rays absent, inflorescence single dense cluster of spikelets, 12–40 mm diam.; bracts (3–)4–6(–7), horizontal to ascending at 45°, flanged V-shaped, (2–)5–15(–23) cm × 1–4 mm. |
spikes loosely ovoid, 8–15(–25) mm wide; rachis 1–3 mm; rays (1–)2–4(–6), (0.5–)1–3(–6) cm; 2d order rays absent; bracts (1–)2–4(–5), ascending at 30–45°, V-shaped, (1–)2.5–6(–11) cm × 0.5–1.8 mm. |
Spikelets | (5–)15–30(–40), spreading to appressed-ascending, linear-lanceoloid to linear, compressed, 8–18(–40) × (1–)1.3–1.6(–2) mm; floral scales (8–)12–25(–66), laterally stramineous to light brown, medially green, laterally ribless, medially 3–5-ribbed, oblong, (1.5–)1.8–2.4 × (1–)1.2–1.4 mm, apex acute to ± acute, mucronate. |
(2–)4–6(–10), linear-lanceoloid, strongly flattened, (5–)8–12(–18) × 1.2–1.5 (1.8) mm; floral scales (5–)10–16(–32), laterally clear, stramineous or light reddish brown, medially green, laterally ribless, medially 3(–5)-ribbed, ovate, (1.2–)1.3–1.6(–2) × 1–1.2(–1.4) mm, apex obtuse, mucronate to minutely mucronulate. |
Flowers | stamens 2; anthers (0.4–)0.5–0.8 mm, connective not prolonged; styles 0.6–1(–1.4) mm; stigmas (1–)1.4–2 mm. |
stamens 2; anthers 0.1–0.2 mm; styles 0.1–0.3(–0.4) mm; stigmas 0.3–0.4 mm. |
Achenes | light to dark brown, oblong, (0.8–)0.9–1.1(–1.2) × 0.4–0.5(–0.6) mm, base cuneate to ± stipelike, apex truncate, apiculate, surfaces punctate to minutely punctate with raised cells. |
light to dark brown, glossy or iridescent, stipitate, oblong-obovoid, 0.9–1.1 × 0.4–0.5 mm, stipe 0.1 mm, apex truncate, apiculate, surfaces punctate. |
Cyperus polystachyos |
Cyperus fugax |
|
Phenology | Fruiting summer–early fall. | Fruiting early summer. |
Habitat | Shores, ditches, swales between dunes | Wet, disturbed sandy soils in full sun |
Elevation | 0–200 m (0–700 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; DC; DE; FL; GA; KY; LA; MA; MD; ME; MS; NC; NJ; NY; OK; PA; SC; TX; VA; WV; Mexico; Central America; South America; Asia; Africa
|
LA; TX; Central America; West Indies (Cuba); South America (Ecuador) |
Discussion | Cyperus polystachyos is polymorphic. Adequate understanding of the infraspecific variations of C. polystachyos requires a worldwide examination, which is beyond the scope of this study. The segregates, C. fugax and C. filicinus, are recognized here; they have been usually accepted by recent workers (e.g., M. L. Fernald 1950; H. A. Gleason and A. Cronquist 1991). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cyperus fugax is known from Louisiana from an early nineteeth century collection from “western Louisiana” (Hale s.n., TCD). Cyperus fugax has been treated as a form of C. polystachyos (G. Kükenthal 1935–1936; A. B. Ayers 1946); nevertheless, specific status is appropriate. The most conspicuous differences are the annual habit and small size (less than 12 cm) of C. fugax; C. polystachyos is a perennial of moderate size (mostly taller than 20 cm). Other differences are summarized below. Cyperus polystachyos is characterized as a shortly rhizomatous perennial; floral scales oblong, 1.8–2.4 mm, closely imbricate; styles 0.6–1 mm; stigmas 1.4–2 mm; anthers 0.6–0.8 mm; achenes substipitate to cuneate, slightly compressed laterally. Cyperus fugax is characterized as a nonrhizomatous annual; floral scales ovate, 1.3–1.6 mm, loosely imbricate; styles 0.1–0.2 mm; stigmas 0.3–0.4 mm; filaments 1.2–1.4 mm; anthers 0.1–0.2 mm; achenes stipitate, strongly compressed laterally. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 160. | FNA vol. 23, p. 159. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Pycreus |
Sibling taxa | ||
Synonyms | C. brizaeus, C. polystachyos var. leptostachyus, Pycreus polystachyos | C. inconspicuus, C. tenellus |
Name authority | Rottbøll: Descr. Pl. Rar., 21. (1772) | Liebmann: Kongel. Danske Vidensk. Selsk. Skr., Naturvidensk. Math. Afd., ser. 5, 2: 196. (1850) |
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