The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

featherbristle beaksedge

Habit Plants perennial, densely cespitose, knottybased, 20–40 cm; rhizomes absent. Plants perennial, densely cespitose, 15–50(–60) cm; rhizomes absent.
Culms

filiform, leafy at base, wiry.

erect or arching, leafy toward base, filiform, terete, wiry.

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.

overtopped by culm;

blades linear to filiform, channeled, 0.3–0.5 mm wide, margins deeply involute, apex setaceous.

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.

spikelet clusters 1–2(–3), dense to open, narrowly to broadly turbinate;

branches capillary, variously elongate; leafy bracts setaceous, equaling or 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.

variously brown, ellipsoid, 2–3 mm, apex sharply acute;

fertile scales ovate to nearly orbiculate, rounded, 1.2–1.8 mm, apiculate, convexcupulate, midrib slender, mostly included.

Flowers

perianth bristles 6, reaching to or slightly past tubercle base, increasingly plumose from middle to base.

perianth absent.

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.

2–3 per spikelet, 0.7–0.9(–1) mm;

body pale, obovoid-lenticular, (0.5–)0.6–0.9 × 0.4–0.5 mm, margin wirelike;

surfaces transversely rugulose;

tubercle buttonlike, depressed triangular, 0.05–0.1 mm, base lunate atop rounded fruit body.

Rhynchospora oligantha

Rhynchospora pusilla

Phenology Fruiting spring–summer. Fruiting summer–fall.
Habitat Sands and peats of bogs, depressions in savannas, open pinelands, seeps Moist sands, peats and silts of low meadows, savannas, bogs, seeps, pond shores
Elevation 0–200 m (0–700 ft) 0–300 m (0–1000 ft)
Distribution
from FNA
AL; DC; DE; FL; GA; LA; MS; NC; NJ; SC; TX; VA; Central America; West Indies
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC; TX; Mexico; Central America; West Indies
[BONAP county map]
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.)

Source FNA vol. 23, p. 218. FNA vol. 23, p. 220.
Parent taxa Cyperaceae > Rhynchospora Cyperaceae > Rhynchospora
Sibling taxa
R. alba, R. baldwinii, R. brachychaeta, R. breviseta, R. caduca, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. fusca, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. latifolia, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. mixta, R. nitens, R. nivea, R. odorata, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. pusilla, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
R. alba, R. baldwinii, R. brachychaeta, R. breviseta, R. caduca, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. fusca, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. latifolia, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. mixta, R. nitens, R. nivea, R. odorata, R. oligantha, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
Synonyms Phaeocephalum pusillum, R. intermixta
Name authority A. Gray: Ann. Lyceum Nat. Hist. New York 3: 212. (1835) Chapman ex M. A. Curtis: Amer. J. Sci. Arts, ser. 2, 7: 409. (1849)
Web links