Cyperus tetragonus |
Cyperus pilosus |
|
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fourangle flatsedge |
fuzzy flatsedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, annual or perennial, cespitose; stolons slender, to 5 cm × 1.5 mm. |
Culms | trigonous, (20–) 30–80 cm × 1–2.5 mm, glabrous or occasionally with scattered prickles on distal angles. |
trigonous, 25–90 cm × 2 mm, hispidulous or glabrous on angles distally. |
Leaves | 9–11, flat to slightly V-shaped, 25–80 cm × 3.5–10 mm. |
flat, 10–35 cm × 3–10 mm. |
Inflorescences | spikes (1–)3–6, loosely cylindric or oblong with parallel sides, 1.5–4 cm × 10–17 mm; rays 6–12, 2–25 cm, glabrous or rarely scabridulous proximal to spikes; bracts 6–11, ascending at 45°, flat, (1–)10–20(–26) cm × 1–10 mm; rachilla deciduous, wings persistent, 0.4–0.5 mm wide. |
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 | 10–60, narrowly ellipsoid, quadrangular, 5–8 × 1.5–2 mm; floral scales persistent, (2–)3–7, appressed, clear at maturity, laterally reddish to purplish brown, medially greenish, often erose at maturity, laterally 3–5-ribbed, medially 3-ribbed, ovate-elliptic, 2.5–3.2 × 1.8–2.1 mm, apex obtuse. |
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 | anthers 0.8–1 mm; styles 0.3–0.5 mm; stigmas 2–2.5 mm. |
anthers 0.4 mm; styles 0.6 mm; stigmas 1 mm. |
Achenes | brown to reddish brown, sessile, oblong-ovoid to broadly ellipsoid, slightly dorsiventrally flattened, 1.8–2 × 0.7–0.8 mm, apex obtuse, apiculate, surfaces papillose to puncticulate. |
brown, sessile, broadly ellipsoid, 1–1.2 × 0.5 mm, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus tetragonus |
Cyperus pilosus |
|
Phenology | Fruiting summer–fall (Jun–Nov). | Fruiting summer. |
Habitat | Open woods, thickets, barrier islands | Rice fields, wetlands, emergent muddy shores |
Elevation | 0–1000 m (0–3300 ft) | 0–50 m (0–200 ft) |
Distribution |
AL; AZ; FL; GA; MS; NC; NM
|
FL; LA; MS; SC; Asia [Introduced in North America]
|
Discussion | The status of Cyperus pringlei from the southwestern United States requires further study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 23, p. 189. | FNA vol. 23, p. 166. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. pringlei, C. tetragonus var. pringlei, Mariscus tetragonus | |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 71. (1821) | Vahl: Enum. Pl. 2: 354. (1805) |
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