Cyperus tetragonus |
Cyperus giganteus |
|
---|---|---|
fourangle flatsedge |
giant flatsedge, Mexican papyrus |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, rhizomatous, stout. |
Culms | trigonous, (20–) 30–80 cm × 1–2.5 mm, glabrous or occasionally with scattered prickles on distal angles. |
roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
Leaves | 9–11, flat to slightly V-shaped, 25–80 cm × 3.5–10 mm. |
bladeless. |
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 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. |
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–)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. |
Flowers | anthers 0.8–1 mm; styles 0.3–0.5 mm; stigmas 2–2.5 mm. |
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. |
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. |
pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
Cyperus tetragonus |
Cyperus giganteus |
|
Phenology | Fruiting summer–fall (Jun–Nov). | Fruiting summer. |
Habitat | Open woods, thickets, barrier islands | Stream banks, marshes |
Elevation | 0–1000 m (0–3300 ft) | 0–10 m (0–0 ft) |
Distribution |
AL; AZ; FL; GA; MS; NC; NM
|
LA; TX; Mexico; Central America; South America; West Indies [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 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. 189. | FNA vol. 23, p. 173. |
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: 364. (1805) |
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