Rhynchospora fascicularis |
Rhynchospora oligantha |
|
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fascicled beaksedge |
featherbristle beaksedge |
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Habit | Plants perennial, cespitose, 100–150 cm; rhizomes absent. | Plants perennial, densely cespitose, knottybased, 20–40 cm; rhizomes absent. |
Culms | erect to excurvedascending, narrowly linear to ± filiform, terete to obscurely trigonous, leafy, densely so toward base, stiff to rather lax. |
filiform, leafy at base, wiry. |
Leaves | overtopped by culm; blades linear, ascending, proximally flat, 1–4 mm wide, apex trigonous, subulate, tapering gradually. |
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. |
Inflorescences | spikelet clusters 1–3(–4), proximal mostly widely spaced, dense, broadly turbinate to hemispheric, to 2 cm broad; leafy bracts subulate, exceeding proximal spikelets, slightly or not exceeding most distal clusters. |
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. |
Spikelets | redbrown, narrowly ovoid, (3–)3.5–5 mm, apex acute; fertile scales ovate, 3–3.5(–4) mm, apex acute, mostly with cusp or mucro 0.5–1 mm. |
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. |
Flowers | bristles 5–6, from rudimentary to reaching tubercle tip, or (rarely) beyond, antrorsely barbellate. |
perianth bristles 6, reaching to or slightly past tubercle base, increasingly plumose from middle to base. |
Fruits | 1–3 per spikelet, (1.5–)2–2.2(–2.5) mm; body dark brown with pale center, lenticular, broadly ellipsoid to ± orbicular, (1.3–)1.5–1.7(–1.9) × 1–1.5 mm, margins pale, narrow or narrowly rounded, flowing to tubercle; surfaces dull, minutely longitudinally striate; tubercle compressed, triangular to triangularsubulate, 0.5–0.7(–0.9) mm. |
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. |
Rhynchospora fascicularis |
Rhynchospora oligantha |
|
Phenology | Fruiting late spring–fall or all year (south). | Fruiting spring–summer. |
Habitat | Sands and peats of interdunal swales, depressions in savannas, open flatwoods, and seep-bog edges | Sands and peats of bogs, depressions in savannas, open pinelands, seeps |
Elevation | 0–100 m (0–300 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC; TX; VA; Central America; Bermuda
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AL; DC; DE; FL; GA; LA; MS; NC; NJ; SC; TX; VA; Central America; West Indies
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Discussion | In her revision, S. Gale (1944) treated var. distans as the more slender version of the species, one with a smaller inflorescence, more distinctly margined fruit body, and consistently elongate perianth bristles. All those character states appear to vary independently over the total range of the species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 23, p. 239. | FNA vol. 23, p. 218. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Schoenus fascicularis, Dichromena distans, Phaeocephalum fasciculare, Phaeocephalum distans, R. distans, R. distans var. fascicularis, R. dommucensis, R. fascicularis var. distans, Schoenus distans | |
Name authority | (Michaux) Vahl: Enum. Pl. 2: 234. (1805) | A. Gray: Ann. Lyceum Nat. Hist. New York 3: 212. (1835) |
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