Cyperus flavescens |
Cyperus mutisii |
|
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pale flatsedge, yellow flatsedge |
mutis' flatsedge |
|
Habit | Herbs, annual, cespitose. | Herbs, perennial, cespitose, rhizomatous. |
Culms | trigonous, (2–)4–30 cm × 0.4–2 mm, glabrous. |
trigonous, (20–)30–120 cm × 1.4–3.5 mm, glabrous or occasionally with scattered prickles on distal angles. |
Leaves | 1–5, (blades often absent, base of culm with 1 reddish sheath bearing minute blade tooth 1–2 mm), (3–)10–18 cm × (0.5–)1.5–2(–2.6) mm. |
2–4(–6), inversely W-shaped, 10–60(–70) cm × (2–)4–13 mm, margins and midribs scabridulous or glabrous. |
Inflorescences | spikes 1–3, ovoid or ± digitate, 10–30 × 8–26 mm; rays 1–4(–6), 0.5–3(–9) cm; bracts 2–3, approximately horizontal, 1–12 cm × 0.5–2.5 mm. |
spikes (1–)3–6, narrowly cylindric, 1–4(–6) cm × 5–11 mm; rays 0 or 3–6, 2–23 cm; bracts 5–8, ascending at ± 45°, inversely W-shaped, (4–) 14–40(–46) cm × 1–12 mm; rachilla deciduous, wings persistent, 0.3–0.5 mm wide. |
Spikelets | 1–6, compressed, oblong-lanceoloid, 5–15 × (2–)2.3–2.8 mm; floral scales (4–)8–24, closely imbricate, laterally yellow to yellowish brown, margins light brown to clear, medially green, laterally ribless, medially 2–3-ribbed, 2-keeled basally, ovate, (1.5–)1.8–2.2 × 1.8 mm, apex obtuse. |
35–100, oblong-ellipsoid, ± terete, elliptic in cross section, 3–7 × (0.9–) 1.3–2 mm; distal spikelets spreading or ascending; floral scales persistent, 1–2(–5), appressed, becoming clear at maturity, laterally brownish to reddish brown, medially greenish, laterally 3–5-ribbed, medially 3-ribbed, often erose at maturity, ovate to elliptic, 2.2–3.2 × 1.5–2.1 mm, apex obtuse. |
Flowers | stamens 3; anthers 0.4 mm, connectives not prolonged; styles 0.5–1 mm; stigmas 0.5–0.8 mm. |
anthers 0.6–0.8 mm; styles 0.4–0.8 mm; stigmas 1.2–2.2 mm. |
Achenes | jet black to reddish brown, slightly stipitate, obovoid, 1–1.2 × 0.8 mm, apex apiculate, surface with network of rectangular longitudinally elongate cells and transverse undulations. |
brown to reddish brown, sessile, broadly ellipsoid, slightly dorsiventrally flattened, 1.5–1.8 × 0.7–0.9(–1) mm, apex obtuse, apiculate, surfaces papillose to puncticulate. |
Cyperus flavescens |
Cyperus mutisii |
|
Phenology | Fruiting summer–early fall. | Fruiting summer–fall (Jun–Nov). |
Habitat | Damp, often disturbed soils | Clearings in montane forests, canyons |
Elevation | 0–800 m (0–2600 ft) | 500–1500 m (1600–4900 ft) |
Distribution |
AL; AR; CA; DC; DE; FL; GA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WV; ON; South America; West Indies; Eurasia; Africa
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AZ; Mexico; Central America; South America |
Discussion | North American populations have been distinguished as Cyperus flavescens var. poiformis; their taxonomic separation was not supported by M. L. Corcoran’s (1941) careful study. Plants of Mexico and Central America consistently have purplish rather than yellowish floral scales and may be recognized as C. flavescens var. piceus (Liebmann) Fernald (G. C. Tucker 1983, 1994). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cyperus mutisii is recognized by its cylindric spikes borne digitately at the ends of the rays and its short, plump spikelets. As spikelets mature, the floral scales, having erose margins contrasting with the brownish sides, beome useful distinguishing features. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 162. | FNA vol. 23, p. 189. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. flavescens var. poiformis, C. poiformis, Pycreus flavescens | Mariscus mutisii, C. asper, C. compresso, C. ehrenbergianus, C. mutisii var. asper, C. mutisii var. contractus, C. mutisii var. semitribrachiatus, C. ochreatus, C. semitribrachiatus, Mariscus asper |
Name authority | Linnaeus: Sp. Pl. 1: 46. (1753) | (Kunth) Andersson: Galapagos Veg., 53. (1854) |
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