Cyperus giganteus |
Cyperus sphaerolepis |
|
---|---|---|
giant flatsedge, Mexican papyrus |
Rusby's flatsedge, Rusby's sedge |
|
Habit | Herbs, perennial, rhizomatous, stout. | Herbs, perennial, rhizomatous. |
Culms | roundly trigonous, 200–350 cm × 15–50 mm, glabrous. |
basally cormlike, trigonous, (8–)15–40(–60) cm × (0.4–)0.8–1.5(–2) mm, glabrous or sparsely to densely scabridulous to minutely scabrid on angles or usually on surface, just proximal to bracts or over distal few centimeters. |
Leaves | bladeless. |
(1–)3–4, V-shaped, (7–)15–25(–40) cm × 1–3(–5) mm, sparsely minutely scabridulous on margins and keel in distal 1/3, otherwise glabrous. |
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 1–3, sessile (occasionally 1 spike on peduncle 5–20 cm, produced from axil of distalmost leaf), loosely cylindric to oblong-ovoid, (9–)15–30(–45) × (3–)8–15(–18) mm; bracts 2–3(–7), longest erect, or very nearly so, others spreading, (1–)3–20(–26) cm × (0.5–)1–3(–5) mm; rays (1–)2–6(–11), (1–)2–7(–12) cm, in some depauperate plants rays less than 1 cm; rachilla ± deciduous, 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. |
(4–)8–25(–35), oblong-ellipsoid to linear, compressed-quadrangular, (2–)7–11(–15) × (2–)2.4–3.2(–3.5) mm; floral scales (1–)4–8(–14), laterally dull whitish, stramineous, or light brown, or reddish brown to deep red, often red-dotted especially near keel, medially greenish, broadly ovate-deltate to ± orbiculate, laterally strongly 3(–4)-ribbed, medially weakly 1–3-ribbed, (1.6–)1.8–2.4 × (1.8–)2.2–2.8 mm, margins clear, erose especially apically, apex obtuse, tipped with straight mucro 0.1–0.2(–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 0.4–0.6 mm; styles 0.4(–0.8) mm; stigmas 0.6–1 mm. |
Achenes | pale brown, sessile, oblong, 0.9–1 × 0.4–0.5 mm, apex scarcely apiculate, surfaces puncticulate. |
finely reticulate with isodiametric cells, this layer gradually wearing away to reveal inner brown to reddish brown layer, stipitate, ovoid to obovoid, 1.4–1.6(–1.9) × 1–1.3(–1.4) mm, base cuneate to ± attenuate, stipe 0.1–0.2 × 0.2 mm, apex obtuse, slightly apiculate, inner layer papillose. |
Cyperus giganteus |
Cyperus sphaerolepis |
|
Phenology | Fruiting summer. | Fruiting summer. |
Habitat | Stream banks, marshes | Clearings in montane forests |
Elevation | 0–10 m (0–0 ft) | 1000–2500 m (3300–8200 ft) |
Distribution |
LA; TX; Mexico; Central America; South America; West Indies [Introduced in North America] |
AZ; NM; TX; Mexico |
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 sphaerolepis has long been known by the synonym C. rusbyi and has been treated as a variety of C. fendlerianus. Specific status for C. sphaerolepis is supported by B. G. Marcks (1972) and G. C. Tucker (1994). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 173. | FNA vol. 23, p. 177. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. fendlerianus var. debilis, C. fendlerianus var. leucolepis, C. leucolepis, C. rusbyi, C. schweinitzii var. debilis | |
Name authority | Vahl: Enum. Pl. 2: 364. (1805) | Boeckeler: Linnaea 35: 609. (1868) |
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