Cyperus drummondii |
Cyperus thyrsiflorus |
|
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Drummond's sedge |
southern flatsedge |
|
Habit | Herbs, perennial, cespitose; rhizomes 0.5–2 cm, often absent. | Herbs, perennial, rhizomatous. |
Culms | trigonous, 35–170 cm × 2–4.7 mm, scabrid on angles. |
trigonous, (15–) 20–40(–65) cm × 0.5–1 mm, glabrous. |
Leaves | 4–12, with readily visible cross ribs especially on abaxial surface, flat to V-shaped, 25–100 cm × 2.4–11 mm. |
V-shaped, (10–)20–40 cm × 0.8–2.8(–3) mm, glabrous. |
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. |
spike 1, densely oblong-cylindric, (15–)25–35(–40) × 12–18(–22) mm, (spikelets loosely spaced, 7–9 per 5 mm of rachis); rays (5–)6–8(–11), 0.5–4(–7.5) cm; bracts (4–)5–7(–8), ascending at 30º, (4–)10–30(–35) cm × (1–)2–4(–7) mm; rachilla deciduous, wings persistent, 0.4–0.5 mm wide. |
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. |
(20–)40–80(–100), linear, ± cylindric, scarcely compressed, (4.5–)6–9(–11) × (0.5–) 0.6–0.7(–1) mm; floral scales persistent, (1–)2–3(–4), appressed, medially green, laterally light brown to tawny or bronze, medially (1–)3-ribbed, laterally 3-ribbed, oblong, (2.6–)2.8–3.2(–3.4) × (1–)1.2(–1.4) mm, apex acute, mucronulate, mucro to 0.1(–0.2) mm. |
Flowers | stamens 1–2; anthers 0.8–1.2 mm; styles 0.8–1 mm; stigmas 0.6–0.8 mm. |
anthers 0.6–0.8 mm; styles (0.4–)0.6–1(–1.2) mm; stigmas persistent on achenes, prominently exserted from floral scales, (1.5–)2–3(–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 to reddish brown, stipitate, narrowly oblong, 1.8–2.1 × (0.4–)0.5(–0.7) mm, stipe 0.1–0.2 × 0.1–0.2 mm, apex apiculate, acute, surfaces puncticulate. |
Cyperus drummondii |
Cyperus thyrsiflorus |
|
Phenology | Fruiting late spring–summer. | Fruiting summer. |
Habitat | Wet, relatively undisturbed habitats, especially flatwoods, ponds, seepage slopes, coastal prairies | Dry, open woods |
Elevation | 0–200 m (0–700 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; FL; GA; LA; MS; SC; TX; Central America; South America; West Indies |
AL; FL; GA; LA; TX; Mexico; South America; West Indies |
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.) |
|
Source | FNA vol. 23. | FNA vol. 23, p. 185. |
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 | C. anceps, C. dissitiflorus, C. pallens, C. regiomontanus var. pallens, C. tribrachiatus, Mariscus dissitiflorus, Mariscus pallens, Mariscus tribrachiatus |
Name authority | Torrey & Hooker: Ann. Lyceum Nat. Hist. New York 3: 437, errata. (1836) | Junghuhn: Linnaea 6: 24. (1831) |
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