Cyperus giganteus |
Cyperus |
|||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
giant flatsedge, Mexican papyrus |
cyperus, flatsedge, galingale, nutsedge, umbrella-sedge |
|||||||||||||||||
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, perennial or less often annual, cespitose or not, rhizomatous, stoloniferous, rarely tuberous. | ||||||||||||||||
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
solitary or not, trigonous or round, glabrous or scabridulous with extrorse or antrorse (rarely retrorse) prickles. |
||||||||||||||||
Leaves | bladeless. |
usually basal; ligules absent; blades keeled abaxially, flat, V-, or inversely W-shaped in cross section. |
||||||||||||||||
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. |
terminal, rarely pseudolateral, 1st order subumbellate to capitate, 2d order with spicate or digitately arranged spikelets, rarely a solitary spikelet; spikelets 1–150; 1st order rays unequal (rarely equal) in length, produced singly from the axils of inflorescence bracts; involucral bracts 1–22, spirally arranged at culm apex, spreading to erect, leaflike. |
||||||||||||||||
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. |
scales to 76, distichous, each subtending flower, cylindric to compressed, borne spicately or digitately at ends of rays (occasionally proliferous). |
||||||||||||||||
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. |
bisexual [rarely unisexual], in axils of distichous floral scales, bases often decurrent onto rachilla as ± hyaline wings; perianth absent; stamens 1–3; styles linear, 2–3-fid, base deciduous or persistent; stigmas 2–3. |
||||||||||||||||
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
biconvex, flattened, or trigonous. |
||||||||||||||||
Cyperus giganteus |
Cyperus |
|||||||||||||||||
Phenology | Fruiting summer. | |||||||||||||||||
Habitat | Stream banks, marshes | |||||||||||||||||
Elevation | 0–10 m (0–0 ft) | |||||||||||||||||
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
Pantemperate and tropical |
||||||||||||||||
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.) |
Species ca. 600 (96 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||||||||||
Key |
|
|||||||||||||||||
Source | FNA vol. 23, p. 173. | FNA vol. 23, p. 141. | ||||||||||||||||
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Linnaeus: Sp. Pl. 1: 44. (1753): Gen. Pl. ed. 5, 26. (1754) | ||||||||||||||||
Web links |
|