Cyperus seslerioides |
Cyperus diandrus |
|
---|---|---|
Texas flatsedge |
umbrella flat sedge |
|
Habit | Herbs, perennial, cespitose; rhizomes knotty, much branched, 2–5 mm diam., scaly. | Herbs, annual, 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. |
trigonous, 4–25(–35) cm, glabrous. |
Leaves | 1–5, flat, involute toward apex, 3–18 cm × 1–2.5(–3) mm. |
flat, 5–20 cm × 1.5–3 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. |
heads ± digitate, 12–22 mm diam.; rays 3–6, 1–6 cm; bracts 1–4, ± horizontal, flat, 1.5–15 cm × 1.5–3 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. |
6–12, oblong-lanceoloid, compressed, 5–10 × 2.8–3.2 mm; floral scales 8–28, closely imbricate, stramineous to light brown or clear (marginal band bright red, spikelet thus appearing dark margined), laterally ribless, oblong to ovate, 2.5–3 × 1.6–1.9 mm. |
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 0.3 mm, connective apex reddish, subulate, 0.1–0.2 mm; styles 0.3–0.5 mm; stigmas 2.2–3.1 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. |
brown, network of ridges forming isodiametric or square cells, sessile or stipitate, obovoid to ovoid, 1–1.2 × 0.5–0.6 mm, stipe, if present, 0.1 mm, apex obtuse, apiculate, surfaces minutely punctate. |
Cyperus seslerioides |
Cyperus diandrus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Seeps, damp meadows in montane forests | Emergent shorelines, in sandy, peaty, or slightly brackish areas (though seldom where disturbed) |
Elevation | 1000–2000 m (3300–6600 ft) | 0–600 m (0–2000 ft) |
Distribution |
AZ; TX; Mexico; South America; Central America (Honduras) |
CT; DE; IA; IL; IN; MA; MD; ME; MI; MN; MO; NE; NH; NJ; NY; PA; RI; VA; VT; NB; NS; ON; QC
|
Source | FNA vol. 23, p. 157. | FNA vol. 23, p. 161. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Pycreus diander | |
Name authority | Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 1: 209. (1816) | Torrey: Cat. Pl. New York, 90. (1819) |
Web links |
|