Rhynchospora latifolia |
Rhynchospora breviseta |
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sandswamp whitetop |
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Habit | Plants perennial, cespitose or solitary, to 100 cm; rhizomes scaly, 3–4 mm thick. | Plants perennial, densely cespitose, knottybased, 20–40 cm; rhizomes absent. |
Culms | arching or erect, leafy-based, distally wandlike, terete, multiribbed. |
leafy at base, filiform, wiry. |
Leaves | ascending to spreading, overtopped by scape; blades linear, proximally flat, 2.5–5 mm wide, apex subulate, trigonous. |
blades filiform, nearly reaching inflorescence tip or much shorter, to 0.3 mm thick, apex tapering. |
Inflorescences | terminal, headlike clusters of spikelets, clusters dense, leafy-involucrate; involucral bracts several, spreading to downcurved, longest 6–13 cm × 5–10 mm, mostly white to midbract, then green, abruptly narrowly linear. |
spikelet clusters mostly 2–6, simple or reduced to 1 spikelet, often with 2 capillary branches, one divaricate or reflexed, 1 ascending; leafy bracts single per cluster, filiform, setaceous, with clusters appearing lateral to bracts. |
Spikelets | white, ovoid, 5–7 mm; fertile scales boatshaped, sharply curved-keeled, 5 mm, apex acute. |
pale redbrown, ellipsoidlanceoloid, 5–6(–8) mm, apex acute to acuminate; fertile scales narrowly ovate, 3–5(–6) mm, apex acute, midrib included or shortexcurrent. |
Flowers | perianth absent. |
perianth bristles 6, not reaching past fruit midbody, stubby, plumose to near tip. |
Fruits | several per spikelet, 1.5–2 mm; body yellowish to deep brown, tumidly lenticular, broadly obovoid to orbicular or oblate, 1.5 mm, widest at or toward midbody, margins flowing to tubercle; surfaces with many fine rows of vertical shallow lattices, their contiguous ends making transverse rows of papillae; tubercle crescent-based, depressed-triangular, 0.5 mm, apex acute. |
3–8 per spikelet, 2–2.5 mm; body light brown to brown, ellipsoid-obovoid, tumidly lenticular, 1.5–2 × 1.6–1.7 mm; surfaces faintly, interruptedly crossrugulose, apically indented under tubercle; tubercle lowconic, 0.5 mm, base flaring, circular. |
2n | = 12. |
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Rhynchospora latifolia |
Rhynchospora breviseta |
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Phenology | Fruiting late spring–summer. | Fruiting spring–summer. |
Habitat | Sands and peats of bogs in pine savannas and flatwoods | Moist to wet sands or peats of bogs, depressions in savannas, open pinelands, pond shores |
Elevation | 0–200 m (0–700 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX
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AL; FL; GA; LA; MS; NC; SC; VA; West Indies |
Discussion | A specimen collected near Tullahoma, Tennessee, reported as Dichromena latifolia (A. Gattinger 1901), was later destroyed by fire. I did not see the specimen, nor was a description of it published. Because extant populations of the similar Rhynchospora colorata are just over the border in Alabama, that species is likely to have been the one found by Gattinger. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Rhynchospora breviseta is sympatric with R. oligantha over much of its range; intergrades have not been seen. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23. | FNA vol. 23. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Dichromena latifolia, R. stellata var. latifolia | R. oligantha var. breviseta |
Name authority | (Baldwin) W. W. Thomas: Mem. New York Bot. Gard. 37: 86. (1984) | (Gale) Channell: Rhodora 58: 336. (1956) |
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