Cyperus seslerioides |
Cyperus bipartitus |
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Texas flatsedge |
shining flatsedge, slender flatsedge |
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Habit | Herbs, perennial, cespitose; rhizomes knotty, much branched, 2–5 mm diam., scaly. | Herbs, annual, densely cespitose, with fibrous roots. |
Culms | roundly trigonous, basally with dark fibrous remnants of old leaf sheaths, (0.5–)4–30 cm × 0.4 –1.1 mm, glabrous. |
roundly trigonous, 3–25(–30) cm × 0.3–1.4 mm, glabrous. |
Leaves | 1–5, flat, involute toward apex, 3–18 cm × 1–2.5(–3) mm. |
1–3, V-shaped, 1–8 cm × 1–2 mm. |
Inflorescences | heads hemispheric to spheric, (3–)6–15(–24) mm diam.; rays absent; bracts 2–5, horizontal to reflexed, parallel to culm, 1–13 cm × 1–3 mm, margins and keel sparsely minutely scabridulous distally. |
spike 1, loosely ovoid, compressed, 7–14 × 9–14 mm; rays 1–4, to 2(–3) cm; bracts 2–3, horizontal to ascending at 30(–45)°, V-shaped to flat, 1–12 cm × 0.5–1.5 mm. |
Spikelets | (5–)20–60(–100), whitish to greenish or brownish, ovoid to oblong-lanceoloid, compressed, 3–7 × 2–4 mm; floral scales (8–)10–12(–24), laterally milky white (infrequently yellowish, pale greenish, brown, or bronze-white), medially green or white, laterally ribless, medially 3-ribbed, ovate to ovate-lanceolate, 1.6–3(–3.4) × 0.8–1.3 mm, apex mucronate to acuminate. |
3–5(–8), flattened, oblong to oblong-lanceoloid, 8–18 × 2–2.6(–3) mm; floral scales (6–)10–26(–32), closely imbricate, laterally light to dark brown, medially light brown, laterally ribless, medially 2–3-ribbed, 2-keeled, oblong to ovate, 1.9–2.7 × 1.8–2.3 mm, apex obtuse. |
Flowers | stamens 3; anthers linear, (0.4–)0.6–0.8(–1.1) mm, connective not prolonged; styles 0.8–1.8 mm; stigmas (0.5–)1–1.5(–2) mm. |
stamens 2–3; anthers 0.4–0.5 mm, connective not prolonged; styles 0.6–1 mm; stigmas 1–1.5 mm. |
Achenes | brown to blackish, trigonous, broadly obovoid, 0.5–1 × 0.3–0.75 mm, base slightly stipelike, ± cuneate to rounded, apex apiculate, papillose. |
black, network of ridges forming isodiametric or square cells, sessile, obovoid to ovoid, 1–1.3(–1.5) × (0.6–)0.8 mm, apex apiculate, surfaces minutely punctate. |
Cyperus seslerioides |
Cyperus bipartitus |
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Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Seeps, damp meadows in montane forests | Emergent shorelines, ditches, puddles, often in disturbed places |
Elevation | 1000–2000 m (3300–6600 ft) | 0–1500 m (0–4900 ft) |
Distribution |
AZ; TX; Mexico; South America; Central America (Honduras) |
AL; AR; AZ; CA; CO; CT; DC; DE; GA; IA; 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; ON; QC; Mexico; Central America; South America
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Source | FNA vol. 23, p. 157. | FNA vol. 23, p. 161. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. rivularis | |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 209. (1816) | Torrey: Ann. Lyceum Nat. Hist. New York 3: 257. (1836) |
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