Rhynchospora caduca |
Rhynchospora cephalantha |
|
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anglestem beaksedge |
bunched beaksedge |
|
Habit | Plants perennial, cespitose, 70–150 cm; rhizomes often present, short, scaly. | Plants perennial, cespitose, 40–100(–150) cm; rhizomes absent. |
Culms | erect or ascending, leafy, trigonous. |
arching, leafy, obscurely and convexly trigonous, multi-ribbed, slender to stoutish. |
Leaves | exceeded by culm; blades linear, proximally 4–7 mm wide, apex trigonous, tapering. |
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Inflorescences | terminal and axillary; clusters 3–6, mostly dense, narrowly to broadly turbinate, branches ascending; leafy bracts exceeeding proximalmost inflorescences. |
spikelet clusters 3–several, widely spaced, often equidistant, mostly hemispheric to globose, occasionally lobed, 1–2 cm thick; bracteal leaves much exceeding subtended inflorescence. |
Spikelets | rich brown, ovoid, (3–)4–5 mm, apex acuminate; fertile scales ovate, 2.5–3.5 mm, apex acuminate, midrib included or shortexcurrent. |
dark red-brown to dark brown, lanceellipsoid to ellipsoid, 4–5(–6) mm, apex acute; fertile scales elliptic, 3–3.5(–4.5) mm, apex acute, midribs 3, laterals indistinct. |
Flowers | perianth bristles mostly 6, exceeding tubercle tip. |
perianth bristles 6, reaching tubercle tip, retrorsely (rarely antrorsely) barbellate. |
Fruits | mostly 3–4 per spikelet, 2–2.2 mm; body brown on short pedicellar (to 0.3 mm) stalk, broadly obovoid, lenticular, 1.3–1.5 × 1–1.5 mm, surfaces transversely rugulose, vertically finely striate and rectangularalveolate; tubercle compressed, triangular acuminate, 0.5–0.8 mm, edges setulose. |
1(–2) per spikelet, 3.5–4(–4.2) mm; body brown with pale center, obovoid distal to stipe, lenticular, 2–2.3 × 1–1.5(–2) mm; tubercle triangular-subulate, (1–)1.5–2 mm, at least 0.5 mm wide at base. |
Principal | leaves overtopped by culm; blades linear, flat proximally, 1.5–3 mm wide, apex tapering, trigonous. |
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Rhynchospora caduca |
Rhynchospora cephalantha |
|
Phenology | Fruiting summer–fall. | Fruiting summer–fall. |
Habitat | Low meadows, clearings, marshes, marsh borders, seeps, bog moats, savannas, ditches, pine flatwoods, swamps | Sandy silts, sands, and peats of shores, boggy streams, seeps, savannas, and savanna bogs |
Elevation | 0–400 m (0–1300 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TN; TX; VA
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AL; DE; FL; GA; LA; MD; MS; NC; NJ; NY; SC; TX; VA
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Discussion | Rhynchospora caduca has its closest relationships with the even more robust R. odorata Grisebach, on the one hand, and the swampinhabiting, more slender, and rhizomatous R. mixta Britton ex Small, on the other. Intergrades with R. odorata appear in Alabama and northwest Florida; intergrades with R. mixta appear where ranges overlap in both the Atlantic and Gulf coastal plains. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
North American plants referred to Rhynchospora axillaris (Lamarck) Britton [Phaeocephala axillare (Lamarck) House by N. L. Britton and A. Brown (1913) and J. K. Small (1933)] are actually R. cephalantha. A photograph of the type specimen of Schoenus axillaris Lamarck (from P) reveals what appears to be an immature top of S. glomeratus [R. glomerata (Linnaeus) Vahl]. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 223. | FNA vol. 23, p. 212. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Phaeocephalum caducum, R. patula | R. cephalantha var. attenuata, R. cephalantha var. pleiocephala |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 62. (1816) | A. Gray: Ann. Lyceum Nat. Hist. New York 3: 218. (1835) |
Web links |