Rhynchospora caduca |
Rhynchospora colorata |
|
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anglestem beaksedge |
starrush whitetop, white star sedge |
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Habit | Plants perennial, cespitose, 70–150 cm; rhizomes often present, short, scaly. | Plants perennial, cespitose or solitary, to 70 cm; rhizomes slender, scaly, to 2 mm thick. |
Culms | erect or ascending, leafy, trigonous. |
erect, slender, leafy-based, trigonous, several-ribbed. |
Leaves | exceeded by culm; blades linear, proximally 4–7 mm wide, apex trigonous, tapering. |
spreading to erect, overtopped by culm; blades narrowly linear, proximally flattened, 0.5–3 mm wide, apex tapering, trigonous. |
Inflorescences | terminal and axillary; clusters 3–6, mostly dense, narrowly to broadly turbinate, branches ascending; leafy bracts exceeeding proximalmost inflorescences. |
terminal, solitary, headlike, dense, white, leafy-involucrate; involucral bracts several, flaring to recurved, white from broadened base nearly to median, then green to tapered tip, longer bracts 13 cm × 2–7 mm. |
Spikelets | rich brown, ovoid, (3–)4–5 mm, apex acuminate; fertile scales ovate, 2.5–3.5 mm, apex acuminate, midrib included or shortexcurrent. |
white, ovoid, 5–7 mm, apex acute; fertile scales many, boatshaped, sharply curvedkeeled, 3–4(–5) mm, apex acute or blunt. |
Flowers | perianth bristles mostly 6, exceeding tubercle tip. |
perianth absent. |
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. |
several per spikelet, 1.5–1.7(–2) mm; body yellow to mahogany, broadly pyriformobovoid, tumidly lenticular, 1 × 0.5–0.7 mm, widest at apex, margins thickened, interrupted at base of tubercle; surfaces transversely undulaterugose, ridges contiguous, of shortlinear papillae; tubercle broadly triangular, 0.5–0.6 mm, graycrustaceous, apex short acuminate. |
2n | = 12. |
|
Rhynchospora caduca |
Rhynchospora colorata |
|
Phenology | Fruiting summer–fall. | Fruiting late spring–summer. |
Habitat | Low meadows, clearings, marshes, marsh borders, seeps, bog moats, savannas, ditches, pine flatwoods, swamps | Sands, peats, and silt of interdunal swales, shores, meadowy swales, and marsh edges, sometimes fens, usually on circumneutral or basic substrates |
Elevation | 0–400 m (0–1300 ft) | 0–300 m (0–1000 ft) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TN; TX; VA
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AL; AR; FL; GA; LA; MS; NC; SC; TX; VA; Mexico; Central America; West Indies; South America (French Guiana)
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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.) |
Rhynchospora colorata is a slender and clonal version of R. latifolia, with a distinct preference for more basic substrates; involucral bracts are very slender and have a longer portion of green, usually reaching well proximal to midbract. See also 16. Rhynchospora latifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 223. | FNA vol. 23, p. 215. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Phaeocephalum caducum, R. patula | Schoenus coloratus, Dichromena cephalotes, Dichromena colorata, Dichromena leucocephala, R. drummondiana, Scirpus cephalotes |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 62. (1816) | (Linnaeus) H. Pfeiffer: Repert. Spec. Nov. Regni Veg. 38: 89. (1935) |
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