Cyperus drummondii |
Cyperus digitatus |
|
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Drummond's sedge |
finger flatsedge |
|
Habit | Herbs, perennial, cespitose; rhizomes 0.5–2 cm, often absent. | Herbs, perennial, rhizomatous, coarse. |
Culms | trigonous, 35–170 cm × 2–4.7 mm, scabrid on angles. |
trigonous, 50–150 cm × 2–15 mm, glabrous (rarely sparsely scabridulous on angles proximal to bracts). |
Leaves | 4–12, with readily visible cross ribs especially on abaxial surface, flat to V-shaped, 25–100 cm × 2.4–11 mm. |
inversely W-shaped, 40–100 cm × 5–15 mm. |
Inflorescences | heads digitate, globose, 1–1.7 cm diam.; rays 3–5, 1–7 cm; 2d order rays absent; bracts 3–5, horizontal to ascending at 30°, with prominent cross ribs, V-shaped, (4–)11–35(–48) cm × 1–6.7 mm (longest 1/2 as long as culm); 2d order bracts absent. |
spikes 1–4, cylindric, (2.5–)3.5–5 × 1.2–1.5 cm; rays 8–10, (1–)15–35 cm; 2d order rays 1–3 cm; bracts 8–12, ascending at 45–60°, (5–)20–80 cm × 3–15 mm; 2d order bracts 3–7 cm × 2–4 mm; rachilla persistent, wings 0.3 mm wide, at achene maturation adaxial edge of wing detaching from rachilla, base remaining firmly attached. |
Spikelets | 10–40, oblong to linear-lanceoloid, 5–1.8 × 1.5–2.2 mm; floral scales 18–42, pale grayish green, turning brownish, proximally greenish or brownish, 2-keeled, weakly to distinctly 1-ribbed, proximal 1/2 2-ribbed, ovate, 1.4–1.6 × 0.9–1.4 mm, acute (sometimes mucronulate), apically glabrous, occasionally scabridulous. |
35–65, slightly compressed, linear, ± quadrangular, 5–8 × 0.8–1.1 mm; floral scales deciduous, 12–16, appressed, marginally clear, laterally reddish along midrib, medially green, laterally 1–2-ribbed, medially strongly 5-ribbed, ovate, 1.6–1.8 × 1.1–1.3 mm, apex mucronulate. |
Flowers | stamens 1–2; anthers 0.8–1.2 mm; styles 0.8–1 mm; stigmas 0.6–0.8 mm. |
anthers 0.4–0.5 mm, connective blunt, at most 0.1 mm; styles 0.8–1 mm; stigmas 0.4 mm. |
Achenes | brown, slightly stipitate, oblong-ellipsoid (2.4–3.9 times longer than wide), 1–1.2 × 0.3–0.5 mm, apical beak 0.1–0.5 mm, surfaces glabrous. |
brown or whitish, sessile, ellipsoid, slightly wider at base, 0.9 × 0.4 mm, surfaces finely puncticulate. |
Cyperus drummondii |
Cyperus digitatus |
|
Phenology | Fruiting late spring–summer. | Fruiting summer. |
Habitat | Wet, relatively undisturbed habitats, especially flatwoods, ponds, seepage slopes, coastal prairies | Wet pastures, stream banks |
Elevation | 0–200 m (0–700 ft) | 0–100 m (0–300 ft) |
Distribution |
AL; FL; GA; LA; MS; SC; TX; Central America; South America; West Indies |
FL; TX; Mexico; Central America; South America; Asia; Africa |
Discussion | Cyperus drummondii has been treated as a synonym (G. C. Tucker 1994), or a variety (G. Kükenthal 1935–1936), or a subspecies of C. virens (M. F. Denton 1978b). Recent quantitative and field studies (J. R. Carter et al. 1999) provided compelling evidence that specific status is appropriate. Compared to Cyperus virens, C. drummondii is a taller species of less disturbed habitats and has narrower spikelets, ovate scales, and fewer inflorescence bracts. Cyperus virens and C. drummondii are readily distinguished from other Cyperus species in the United States by their sharply angled, scabrid culms and conspicuously septate leaf blades. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23. | FNA vol. 23, p. 173. |
Parent taxa | Cyperaceae > Cyperus > subg. Pycnostachys | Cyperaceae > Cyperus > subg. Cyperus |
Sibling taxa | ||
Synonyms | C. robustus, C. virens subsp. drummondii, C. virens var. drummondii, C. virens var. robustus | |
Name authority | Torrey & Hooker: Ann. Lyceum Nat. Hist. New York 3: 437, errata. (1836) | Roxburgh: Fl. Ind. 1: 209. (1820) |
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