Cyperus diandrus |
Cyperus pilosus |
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umbrella flat sedge |
fuzzy flatsedge |
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Habit | Herbs, annual, cespitose, with fibrous roots. | Herbs, annual or perennial, cespitose; stolons slender, to 5 cm × 1.5 mm. |
Culms | trigonous, 4–25(–35) cm, glabrous. |
trigonous, 25–90 cm × 2 mm, hispidulous or glabrous on angles distally. |
Leaves | flat, 5–20 cm × 1.5–3 mm. |
flat, 10–35 cm × 3–10 mm. |
Inflorescences | 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. |
spikes 1–4(–6), loosely oblong-ovoid, 2–3 × 1–2 cm; rays 3–10, 1–16 cm; 2d order rays to 3 cm; rachis hispidulous, prickles slender, 0.1–0.2 mm; bracts 3–5, ± ascending, flat, 5–35 cm × 0.5–5(–7) mm; rachilla persistent, wingless. |
Spikelets | 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. |
15–40, linear-lanceoloid, compressed, 6–12 × 1.5–2 mm; floral scales deciduous, 8–16, light brown with clear border, laterally 2–3-ribbed, ovate, 1.8–2 × 1.2–1.6 mm; apex entire, emarginate, or mucronulate, mucro at most 0.3 mm. |
Flowers | 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. |
anthers 0.4 mm; styles 0.6 mm; stigmas 1 mm. |
Achenes | 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. |
brown, sessile, broadly ellipsoid, 1–1.2 × 0.5 mm, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus diandrus |
Cyperus pilosus |
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Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Emergent shorelines, in sandy, peaty, or slightly brackish areas (though seldom where disturbed) | Rice fields, wetlands, emergent muddy shores |
Elevation | 0–600 m (0–2000 ft) | 0–50 m (0–200 ft) |
Distribution |
CT; DE; IA; IL; IN; MA; MD; ME; MI; MN; MO; NE; NH; NJ; NY; PA; RI; VA; VT; NB; NS; ON; QC
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FL; LA; MS; SC; Asia [Introduced in North America]
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Discussion | Cyperus pilosus was naturalized in the flora from eastern Asia, apparently early in the twentieth century. The combination of hispidulous rachis and loosely oblong-ovoid spikes is sufficient to distinguish Cyperus pilosus from any others with deciduous floral scales. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 161. | FNA vol. 23, p. 166. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | Pycreus diander | |
Name authority | Torrey: Cat. Pl. New York, 90. (1819) | Vahl: Enum. Pl. 2: 354. (1805) |
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