Rhynchospora alba |
Rhynchospora floridensis |
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rhynchospore blanc, white beak-rush, white beaksedge |
Florida whitetop |
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Habit | Plants perennial, densely cespitose, 6–75 cm; rhizomes mostly absent. | Plants perennial, cespitose, 20–50 cm, wiry; rhizomes absent. |
Culms | erect to curved, leafy, obscurely trigonous to nearly terete, few ribbed, slender. |
erect to spreading, leafybased; scapes nearly filiform, nearly trigonous, few ribbed. |
Leaves | spreading to erect, exceeded by scape; blades filiform to linear, proximally flat or involute, becoming involute, 0.4–2 mm wide, apex tapering, trigonous. |
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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. |
terminal, solitary, headlike, dense, white, leafyinvolucrate, 0.5–1 cm wide; involucral bracts 3–6, spreading to recurved, whitebased, greentipped, narrowly linear, longest bract elongatesubulate, 4–8 cm × 2–5 mm. |
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. |
white, ovoid, 4–6 mm; scales several, boatshaped, basal ones with ciliolate keel, fertile ones 3–3.8 mm. |
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. |
1–1.2 mm; body yellow to black, nearly orbicular, tumidly lenticular, 0.8–1 × 0.6–0.7(–1) mm; surface lattices shortlinear, vertical in fine undulating rows, with ends raised to rounded, transverse rugulosities; tubercle lowtriangular, lunate, 0.2–0.3 mm, apex acute, blunt or 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 floridensis |
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Phenology | Fruiting summer–fall. | Fruiting spring–fall, or all year. |
Habitat | Acid, sphagnous, boggy, open sites, poor fens, often on floating mats or peaty interstices of rocky shores | Moist open areas over reef limestones, rocky pine savanna |
Elevation | 0–2000 m (0–6600 ft) | 0–50 m (0–200 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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FL; Mexico (Chiapas, Yucatán); West Indies (Bahamas); Central America (Belize) |
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.) |
Rhynchospora floridensis is much like R. colorata, with which it is often associated; it can be easily distinguished by its strictly cespitose habit and its ciliolate spikelet scale keels. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 214. | FNA vol. 23, p. 216. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Schoenus albus, Dichromena alba, Phaeocephalum album, R. luguillensis, Triodon albus | Dichromena floridensis |
Name authority | (Linnaeus) Vahl: Enum. Pl. 2: 236. (1805) | (Britton) H. Pfeiffer: Repert. Spec. Nov. Regni Veg. 49: 82. (1940) |
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