Cyperus flavescens |
Cyperus filicinus |
|
---|---|---|
pale flatsedge, yellow flatsedge |
fern flatsedge |
|
Habit | Herbs, annual, cespitose. | Herbs, annual, cespitose. |
Culms | trigonous, (2–)4–30 cm × 0.4–2 mm, glabrous. |
trigonous, 5–50 cm × 0.4–2 mm, glabrous. |
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. |
flat, 10–30 cm × 1–3 mm. |
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. |
heads loosely globose, 10–22 mm diam.; rays 0–6, 1–7 cm; bracts 3–6, horizontal to slightly ascending, flat, 3–26 cm × 1–3 mm. |
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. |
6–20, linear-lanceoloid, compressed, 7–30 × 2–3 mm; floral scales 8–28, stramineous to light reddish brown, laterally ribless, ovate, 2.7–3.6 × 1.6–1.8 mm. |
Flowers | stamens 3; anthers 0.4 mm, connectives not prolonged; styles 0.5–1 mm; stigmas 0.5–0.8 mm. |
stamens 2; anthers 0.5 mm, connective apex reddish, subulate, 0.1–0.2 mm; styles 1.9–2.1 mm; stigmas 1–1.3 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, oblong, 1.2–1.6 × 0.6–0.9 mm, base cuneate to ± stipelike, apex obtuse, apiculate, surfaces minutely punctate. |
Cyperus flavescens |
Cyperus filicinus |
|
Phenology | Fruiting summer–early fall. | Fruiting summer. |
Habitat | Damp, often disturbed soils | Swales between dunes, upper edges of tidal marshes, occasionally emergent shorelines, roadsides, inland ditches |
Elevation | 0–800 m (0–2600 ft) | 0(–50) m (0(–200) 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
|
CT; GA; IL; LA; MA; ME; NC; NH; NJ; NY; RI; SC; VA
|
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.) |
|
Source | FNA vol. 23, p. 162. | FNA vol. 23, p. 160. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycreus | Cyperaceae > Cyperus > subg. Pycreus |
Sibling taxa | ||
Synonyms | C. flavescens var. poiformis, C. poiformis, Pycreus flavescens | C. polystachyos var. macrostachyos |
Name authority | Linnaeus: Sp. Pl. 1: 46. (1753) | Vahl: Enum. Pl. 2: 332. (1805) |
Web links |
|