Cyperus giganteus |
Cyperus hystricinus |
|
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giant flatsedge, Mexican papyrus |
bristly flatsedge |
|
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, perennial, cespitose, with well-developed rhizomes. |
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
trigonous, 30–100 cm × 2–4 mm, basally cormlike, glabrous. |
Leaves | bladeless. |
flat to broadly V-shaped, 20–70 cm × 4–6 mm, glabrous except for marginal prickles. |
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 loosely to densely ovoid, oblong (2 times long as wide), 10–12 × 6–9 mm; rays 6–11, 1–16 cm, glabrous; bracts 5–10, ascending at 30–45°, flat, 6–25 cm × 3–6 mm; rachilla persistent, wings 0.5 mm wide, covering nearly entire length of achene. |
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. |
(20–)40–100(–120), proximal spikelets reflexed somewhat, distal ones divaricate, ± terete, lanceoloid, 6–6.8 × 1–1.4 mm; floral scales persistent, 1–2(–3), appressed, golden brown, lanceolate, laterally 5–6-ribbed, 3.8–4.9 × 1.4–1.6 mm, apex mucronate, 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 1–1.3 mm; styles 0.8–1 mm; stigmas 2–3 mm. |
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
brown, sessile, linear, 2.5–2.8 × 0.5–0.7 mm, apex obtuse, apiculate, surfaces muriculate. |
Cyperus giganteus |
Cyperus hystricinus |
|
Phenology | Fruiting summer. | Fruiting late summer–early fall (Jul–Sep). |
Habitat | Stream banks, marshes | Xeric, sandy soils of sand hills and pine barrens |
Elevation | 0–10 m (0–0 ft) | 0–200 m (0–700 ft) |
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
AL; AR; DC; DE; GA; LA; MD; MO; MS; NC; NJ; TX; VA
|
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 hystricinus resembles C. plukenetii and C. retrofractus; it can be readily distinguished from both by its glabrous culms. Overly mature specimens of C. lancastriensis are frequently misidentified as C. hystricinus; C. hystricinus may be confirmed by its narrow, nearly glabrous leaves and bracts, golden brown spikelets, longer, narrower achenes, and elongated rhizome internodes (to 15 mm vs. 5 mm in 76. C. lancastriensis). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 173. | FNA vol. 23. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. retrofractus var. hystricinus | |
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Fernald: Rhodora 8: 127. (1906) |
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