Rhynchospora alba |
Rhynchospora divergens |
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rhynchospore blanc, white beak-rush, white beaksedge |
spreading beaksedge |
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Habit | Plants perennial, densely cespitose, 6–75 cm; rhizomes mostly absent. | Plants perennial, densely cespitose, 10–60 cm; rhizomes absent. |
Culms | erect to curved, leafy, obscurely trigonous to nearly terete, few ribbed, slender. |
erect or spreadingarching, linearfiliform, terete, leafy toward base. |
Leaves | overtopped by culm; blades ascending, filiform, 0.3–0.5 mm wide, margins deeply involute, then channeled, apex trigonous, setaceous. |
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Inflorescences | clusters 1 or 2–3, then widely spaced, narrowly turbinate to hemispheric, 1.5–2.5 cm wide; subtending leafy bracts often exceeded by distal cluster. |
spikelet clusters 1–2(–4), dense(–open), narrowly to broadly turbinate; branches capillary, variously elongate; leafy bracts setaceous, proximal exceeding clusters. |
Spikelets | pale brown to nearly white, ellipsoid, 3.5–5.5 mm, apex acute; fertile scales elliptic, 3–3.5(–4) mm, apex acute or acuminate, midrib excurrent as mucro. |
brownish, lanceellipsoid to fusiform, 2–2.5(–3) mm, apex acute; fertile scales broadly elliptic, 1.5 mm, apex narrowly rounded to broadly acute, apiculate, convexcupulate, midrib narrow, shortexcurrent or included. |
Flowers | perianth bristles 10–12, slightly overtopping tubercle, retrorsely barbellate or rarely smooth, base often setose. |
perianth absent. |
Fruits | 1(–2) per spikelet, (2.3–)2.5–3 mm; body pale brown with paler center, stipitateobovoid, lenticular, 1.5–1.8(–2) × 0.9–1.2 mm; surfaces transversely striate, relatively smooth, rim narrow, flowing to tubercle base; tubercle narrowly triangularsubulate, 0.5–1.2 mm. |
1–3 or more per spikelet, (0.6–)0.7–0.9(–1) mm; body pale, glassy, obovoidlenticular, 0.6–0.7 × 0.4–0.5 mm, margins narrow, wirelike; surfaces finely striate, very finely reticulate; tubercle button depressedtriangular or patelliform, 0.1–0.15 mm, apiculate. |
Principal | leaves mostly overtopped by culm; blades narrowly linear to filiform, proximally flat, 0.5–1.5 mm, apex tapering, trigonous. |
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Rhynchospora alba |
Rhynchospora divergens |
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Phenology | Fruiting summer–fall. | Fruiting summer–fall or all year (south). |
Habitat | Acid, sphagnous, boggy, open sites, poor fens, often on floating mats or peaty interstices of rocky shores | Moist sands, peats, silts or clays of low meadows, bogs, flatwoods, sometimes seeps over calcareous rock |
Elevation | 0–2000 m (0–6600 ft) | 0–300 m (0–1000 ft) |
Distribution |
AK; CA; CT; DE; GA; ID; IL; IN; MA; MD; ME; MI; MN; NC; NH; NJ; NY; OH; OR; PA; RI; SC; TN; VA; VT; WA; WI; WV; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; Fla(?); West Indies (Puerto Rico); South America(?); Eurasia
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AL; FL; GA; LA; MS; NC; SC; TX; Central America; West Indies (Bahamas, Cuba, Dominican Republic) |
Discussion | The smooth-bristled Rhynchospora alba forma laeviseta Gale mostly occurs with the typical antrorsely barbellate type in Pennsylvania, the Great Lakes, British Columbia, Newfoundland, and Nova Scotia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 214. | FNA vol. 23, p. 220. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Schoenus albus, Dichromena alba, Phaeocephalum album, R. luguillensis, Triodon albus | |
Name authority | (Linnaeus) Vahl: Enum. Pl. 2: 236. (1805) | Chapman ex M. A. Curtis: Amer. J. Sci. Arts, ser. 2, 7: 409. (1849) |
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