Rhynchospora harperi |
Rhynchospora oligantha |
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Harper's beaksedge |
featherbristle beaksedge |
|
Habit | Plants perennial, solitary or cespitose, 50–70 cm; rhizomes absent. | Plants perennial, densely cespitose, knottybased, 20–40 cm; rhizomes absent. |
Culms | erect to excurved, leafybased, narrowly linear, ± terete. |
filiform, leafy at base, wiry. |
Leaves | shorter than culm; blades ascending, narrowly linear, proximally flat or margins slightly involute, 0.5–1(–2) mm wide, distally canaliculate, apex trigonous, tapering, subulate. |
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, laterals 0–2, all turbinate to hemispheric, terminal internode usually excurved; leafy bracts setaceous, overtopping inflorescence. |
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, lanceoloid, 5–7 mm, apex acute; fertile scales lanceolate, (2.5–)4–5 mm, apex acute to acuminate; midrib paralleled by several indistinct ribs, excurrent as short awns. |
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 6, reaching from mid tubercle to beyond tip. |
perianth bristles 6, reaching to or slightly past tubercle base, increasingly plumose from middle to base. |
Fruits | 3(–4) per spikelet, 2.1–2.5 mm; stipe and receptacle 0.2–0.3 mm, sparsely setose and setulose; body glossy, brown with pale center, obovoid-lenticular, 1.1–1.5 × 1–1.1 mm, surfaces finely longitudinally lined, variably low papillatecancellate, also often transversely with wavy lines of dark dots; tubercle flattened, triangular-subulate, (0.8–)0.9–1(–1.1) mm, setulose-ciliate. |
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 harperi |
Rhynchospora oligantha |
|
Phenology | Fruiting summer–fall. | Fruiting spring–summer. |
Habitat | Sands and peats of bogs, stream banks, edges of pineland savanna ponds, Hypericum ponds | 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; DE; FL; GA; MD; MS; NC; SC; Central America (Belize)
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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 | Rhynchospora harperi is most abundant in a very special habitat referred to here as the “Hypericum pond.” These are typically shallow ponds in pine savannas, frequently ringed by stands of Nyssa, Taxodium, Ilex, and Cyrilla, but most of the pond itself is dominated by one or more myriandrous shrubby Hypericum species. Here R. harperi is distinguished from other species by the often abrupt bend of its ultimate internode. (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. 233. | FNA vol. 23, p. 218. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | R. fascicularis var. harperi, R. leptorhyncha | |
Name authority | Small: Man. S.E. Fl., 182, 1503. (1933) | A. Gray: Ann. Lyceum Nat. Hist. New York 3: 212. (1835) |
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