Cyperus giganteus |
Cyperus pilosus |
|
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giant flatsedge, Mexican papyrus |
fuzzy flatsedge |
|
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, annual or perennial, cespitose; stolons slender, to 5 cm × 1.5 mm. |
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
trigonous, 25–90 cm × 2 mm, hispidulous or glabrous on angles distally. |
Leaves | bladeless. |
flat, 10–35 cm × 3–10 mm. |
Inflorescences | spikes loosely cylindric, 15–40 × 8–16 mm; rays 5–8, ascending to erect, stiff,20–30 cm; 2d order rays 5–15 cm; bracts 10–12, ascending at 30–60°, flat, (8–) 20–45 cm × 4–12 mm; 2d order bracts (5–)15–25 cm × 1.5–5 mm; rachilla persistent, separating laterally, remaining firmly attached basally, wings 0.3–0.4 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 | (15–)50–80, slightly compressed, linear, ± quadrangular, 5–12 × 0.6–1.4 mm; floral scales 8–20, appressed, reddish beside 5-ribbed green medial part, white to hyaline near margins, ovate, 1.8–2.2 × 1.2–1.5 mm, apex acute to 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 0.7–1 mm (connective prolonged beyond anther as red subulate appendage 0.2–0.5 mm, its apex sometimes setose); styles 0.2–0.5 mm; stigmas (0.8–)1.2–1.8 mm. |
anthers 0.4 mm; styles 0.6 mm; stigmas 1 mm. |
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
brown, sessile, broadly ellipsoid, 1–1.2 × 0.5 mm, apex obtuse, apiculate, surfaces puncticulate. |
Cyperus giganteus |
Cyperus pilosus |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, marshes | Rice fields, wetlands, emergent muddy shores |
Elevation | 0–10 m (0–0 ft) | 0–50 m (0–200 ft) |
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
FL; LA; MS; SC; Asia [Introduced in North America]
|
Discussion | Cyperus giganteus was erroneously reported from Florida, a misidentification of C. papyrus (R. R. Haynes and A. Lasseigne 1969). Recently, some nurseries specializing in water plants have begun to offer C. giganteus under the name “Mexican papyrus.” Escaped cultivated plants may be expected in southeastern and southwestern United States. (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. 173. | FNA vol. 23, p. 166. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Vahl: Enum. Pl. 2: 354. (1805) |
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