Cyperus giganteus |
Cyperus amabilis |
|
---|---|---|
giant flatsedge, Mexican papyrus |
foothill flatsedge |
|
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, annual, cespitose. |
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
1–10(–25), roundly trigonous, 3–12 cm × 0.3–0.8 mm, glabrous. |
Leaves | bladeless. |
1–3–(4), 1–6 cm × 1(–1.5) 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. |
if rays absent heads single, dense, sessile, digitate, 5–20 × 10–30 mm, single heads 10–30(–50) mm; rays usually absent, if present 1–8 cm; 2d order rays infrequently present, 1–2 cm; bracts 3–6, erect to oblique, flat to V-shaped,(0.5–)2–10(–15) cm × 0.5–2 mm. |
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. |
5–10(–20), linear to linear-lanceoloid, (5–)8–12(–35) × 1.6–2.3(–2.5) mm; floral scales (6–)16–30(–76), laterally glossy reddish brown to brown, medially greenish, sometimes also reddish or brownish, laterally ribless, medially strongly 3-ribbed, ovate-lanceolate, 1.9–2(–2.3) mm (including prominent excurved cusp of 0.3–0.5 mm) × 0.8–1.1 mm, apex truncate, emarginate, or cuspidate. |
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. |
stamens (1–)2–3; anthers ellipsoid, 0.3 mm, connectives not prolonged; styles 0.3–0.4 mm; stigmas 0.4–0.7 mm. |
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
brown, slightly stipitate, obovoid to oblong, 0.8–0.9 × 0.4–0.5 mm, apex abruptly apiculate, surfaces papillose. |
Cyperus giganteus |
Cyperus amabilis |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, marshes | Seasonally wet, sandy soils |
Elevation | 0–10 m (0–0 ft) | 500 m (1600 ft) |
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
AZ; Mexico; Central America; South America; Asia; Africa |
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.) |
|
Source | FNA vol. 23, p. 173. | FNA vol. 23, p. 158. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | C. amabilis var. macrostachyus, C. aurantiacus, C. aureus, C. aureus var. aurantiacus, C. aureus var. macrostachyus, C. aureus var. oligostachyus, C. microstachyus, C. oligostachyus | |
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Vahl: Enum. Pl. 2: 318. (1805) |
Web links |