Cyperus involucratus |
Cyperus lupulinus |
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umbrella-plant |
Great Plains flatsedge, slender sand sedge |
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Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose, bases cormose; rhizomes knotted, beaded. | ||||
Culms | trigonous, 30–150 cm × 1–5(–8) mm. |
trigonous, (3–)10–50 cm × 0.4–1.2 mm, glabrous. |
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Leaves | bladeless. |
flat, 5–40 cm × 1–3.5 mm. |
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Inflorescences | heads digitate, 15–30(–36) mm diam.; rays (14–)20–22, (2–)5–12(–20) cm; 2d order rays 0.3–3(–4) cm; 3d order rays sometimes present, 0.3–2.5 cm; bracts (4–)18–22, ± horizontal, flat, 15–27 cm × (1.5–)8–12 mm. |
spikes rather densely ovoid to globose, 1.2–3.5 cm; rays 0 or 1–4, 1–6 cm; rachis 1–3.5 mm; bracts 2–4, horizontal to reflexed, flat, 6–25 cm; rachilla ± deciduous, wingless. |
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Spikelets | 8–20, ovoid to linear-lanceoloid, compressed, 5–25 × 1.5–2 mm; floral scales 8–28, laterally whitish or light brown, ± hyaline, medially light brown, laterally ribless, medially 3-ribbed, 2-keeled in proximal 30–60%, deltate-ovate, 1.6–2.4 × (1–)1.2–1.5(–1.7) mm, apex acute. |
15–60, compressed, oblong-lanceoloid, (3–)6–22 × 2.5–4 mm; floral scales deciduous, 5–22, off-white to light reddish brown, laterally 3–5-ribbed, ovate-elliptic, 2.5–4 × 2–2.6 mm, margins loosely spreading or clasping achene, apex entire to mucronate, mucro 0.05–0.2 mm. |
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Flowers | stamens 3; anthers 0.7–1 mm; styles 0.5–1 mm; stigmas 0.6–1 mm. |
anthers 0.3–0.6 mm; styles 1 mm; stigmas 1–1.5 mm. |
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Achenes | brown, sessile or stipitate, broadly ellipsoid, 0.6–0.8 × 0.4–0.6 mm, stipe if present to 0.1 mm, apex obtuse, apiculate, surfaces puncticulate. |
dark brown or black, sessile, oblong-ellipsoid to ellipsoid, 1.7–2.2 × 0.8–1.2 mm, apex obtuse, apiculate, surfaces puncticulate. |
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2n | = 166. |
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Cyperus involucratus |
Cyperus lupulinus |
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Phenology | Fruiting early summer–fall. | |||||
Habitat | Damp, disturbed soils, ditches, stream banks | |||||
Elevation | 0–100(–800) m [0–300(–2600) ft] | |||||
Distribution |
CA; FL; LA; TX; e Africa [Introduced in North America] |
AR; CO; CT; DC; DE; GA; IA; ID; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; NC; NE; NH; NJ; NY; OH; OR; PA; RI; TN; TX; VA; VT; WI; WV; NB; NS; ON; QC
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Discussion | Cyperus involucratus has been collected in New York (R. S. Mitchell and G. C. Tucker 1997). Cyperus involucratus is widely cultivated as a water plant in greenhouses and outdoors in warm-temperate or tropical climates. It has long been misidentified in the flora as C. alternifolius Linnaeus, an endemic of Madagascar (G. C. Tucker 1983). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). Cyperus lupulinus was studied in detail (B. G. Marcks 1974). Ranges of the two subspecies overlap somewhat. Cyperus lupulinus subsp. lupulinus is found chiefly in the Great Plains, and subsp. macilentus is centered in the Northeast. It is seldom difficult to assign specimens to subspecies. The hybrid of Cyperus lupulinus with C. schweinitzii is C. ×mesochorus Geise. It is occasionally encountered with the two parent species in the north-central states (Illinois, Indiana, Michigan, Minnesota, and Wisconsin) and has been recorded once from Quebec. The hybrid is similar in size to C. schweinitzii; it has fewer rays, inflorescence bracts 30–45º above horizontal, and floral scales with mucros 0.4–0.5 mm. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 23, p. 150. | FNA vol. 23, p. 176. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Scirpus lupulinus | |||||
Name authority | Rottbøll: Descr. Pl. Rar., 22. (1772) | (Sprengel) Marcks: Trans. Wisconsin Acad. Sci. 62: 271. (1974) | ||||
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