Rhynchospora oligantha |
Rhynchospora pineticola |
|
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featherbristle beaksedge |
pine barren beaksedge |
|
Habit | Plants perennial, densely cespitose, knottybased, 20–40 cm; rhizomes absent. | Plants perennial, mostly densely cespitose, 20–70 cm, base deep rich redbrown; rhizomes absent. |
Culms | filiform, leafy at base, wiry. |
erect to ascending, leafy, stiff. |
Leaves | ascending to erect; blades filiform, nearly terete, or channeled, sometimes compressed, nearly reaching distal inflorescence or much shorter, 0.2–0.3 mm thick, apex subulate. |
shorter than scape; blades narrowly linear, (1–)2–3 mm wide, margins involute, apex trigonous, tapering. |
Inflorescences | spikelet clusters 2–6, simple or reduced to 1 spikelet, branches ascending to divaricate or reflexed; leafy bracts single per cluster, filiform, setaceous, with clusters appearing lateral to bracts. |
clusters 1–2, if 2 then close together, dense, broadly turbinate to hemispheric or lobedglobose; primary leafy bract linear, stiff, exceeding clusters. |
Spikelets | pale redbrown, ellipsoidlanceoloid, 5–6(–8) mm, apex acute to acuminate; fertile scales oblongelliptic, convex, acuminate, 3.5–5 mm, apex broadly acute, midrib forming apiculus. |
light to dark redbrown, lanceovoid, 3.5–6 mm, apex acuminate; fertile scales ovate, convex, 3–3.5(–4) mm, apex acuminate, low midrib excurrent or not. |
Flowers | perianth bristles 6, reaching to or slightly past tubercle base, increasingly plumose from middle to base. |
perianth bristles 6, reaching at least to tubercle base, plumose from base to more than 1/2 length of fruit body. |
Fruits | 1–3 per spikelet, (2.5–)2.7–3(–3.4) mm; body light brown to brown, ellipsoidobovoid, distally conspicuously necked, tumidly lenticular, 1.7–2.5 × 1.5–1.8 mm; surfaces smooth or minutely transversely rugulose; tubercle conicsubulate, 0.5–0.7 mm, base flaring. |
1(–2) per spikelet, (2–)2.5–2.8(–3) mm; body redbrown or brown, tumidly obovoid, (1.5–)2–2.2 × 1–1.7 mm; surfaces interruptedly transversely rugulose; tubercle broadly conic, 0.5–0.8(–1) mm, base broadly 2lobed, apex often apiculate. |
Rhynchospora oligantha |
Rhynchospora pineticola |
|
Phenology | Fruiting spring–summer. | Fruiting spring–fall or all year. |
Habitat | Sands and peats of bogs, depressions in savannas, open pinelands, seeps | Sands and sandy peat of bog margins, pinelands and pine saw palmetto flats among wiregrass |
Elevation | 0–200 m (0–700 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; DC; DE; FL; GA; LA; MS; NC; NJ; SC; TX; VA; Central America; West Indies
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FL; West Indies (Cuba)
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Discussion | Rhynchospora oligantha is distinguished from other taxa of its complex mostly by the distinctive neck at the achene apex, a feature essentially absent in R. breviseta, its closest relative. Those two species have been heavily impacted by conversion of pine savannas to cropland or pine plantations; even with abandonment or clearing of such land, they are very slow to reoccupy the disturbed sites. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Rhynchospora pineticola is distinguished from taller extremes of R. plumosa by its thicker leaves and scapes and its longer spikelets and fruit. Its bases are a deep rich red-brown rather than the pale brown or dull deep brown of R. plumosa. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 218. | FNA vol. 23, p. 219. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Phaeocephalum intermedium, R. intermedia, R. plumosa var. intermedia | |
Name authority | A. Gray: Ann. Lyceum Nat. Hist. New York 3: 212. (1835) | C. B. Clarke: Bull. Misc. Inform. Kew, addit. ser. 8: 40. (1908) |
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