Cyperus tetragonus |
Cyperus drummondii |
|
---|---|---|
fourangle flatsedge |
Drummond's sedge |
|
Habit | Herbs, perennial, cespitose, rhizomatous. | Herbs, perennial, cespitose; rhizomes 0.5–2 cm, often absent. |
Culms | trigonous, (20–) 30–80 cm × 1–2.5 mm, glabrous or occasionally with scattered prickles on distal angles. |
trigonous, 35–170 cm × 2–4.7 mm, scabrid on angles. |
Leaves | 9–11, flat to slightly V-shaped, 25–80 cm × 3.5–10 mm. |
4–12, with readily visible cross ribs especially on abaxial surface, flat to V-shaped, 25–100 cm × 2.4–11 mm. |
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. |
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. |
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. |
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. |
Flowers | anthers 0.8–1 mm; styles 0.3–0.5 mm; stigmas 2–2.5 mm. |
stamens 1–2; anthers 0.8–1.2 mm; styles 0.8–1 mm; stigmas 0.6–0.8 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. |
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. |
Cyperus tetragonus |
Cyperus drummondii |
|
Phenology | Fruiting summer–fall (Jun–Nov). | Fruiting late spring–summer. |
Habitat | Open woods, thickets, barrier islands | Wet, relatively undisturbed habitats, especially flatwoods, ponds, seepage slopes, coastal prairies |
Elevation | 0–1000 m (0–3300 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; AZ; FL; GA; MS; NC; NM
|
AL; FL; GA; LA; MS; SC; TX; Central America; South America; West Indies |
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 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, p. 189. | FNA vol. 23. |
Parent taxa | Cyperaceae > Cyperus > subg. Cyperus | Cyperaceae > Cyperus > subg. Pycnostachys |
Sibling taxa | ||
Synonyms | C. pringlei, C. tetragonus var. pringlei, Mariscus tetragonus | C. robustus, C. virens subsp. drummondii, C. virens var. drummondii, C. virens var. robustus |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 71. (1821) | Torrey & Hooker: Ann. Lyceum Nat. Hist. New York 3: 437, errata. (1836) |
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