Rhynchospora decurrens |
Rhynchospora kunthii |
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swampforest beaksedge |
Kunth's beaksedge |
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Habit | Plants perennial, cespitose, to 100 cm; rhizomes sometimes produced, short, not stoloniferous. | Plants solitary or in small tufts, (5–)10–70 cm, clonal; rhizomes strongly present, stoloniferous. |
Culms | lax, erect to ascending-excurved, ± terete, leafy, slender, soft. |
leafiest toward base, ± trigonous, slender. |
Leaves | exceeded by inflorescence; blades erect or ascending, linear, proximally flat, 2–4 mm wide, apex trigonous, subulate, tapering. |
basal leaves spreadingascending, distal more erect, mostly exceeded by culms (except in highaltitude forms); blades proximally flat or strongly folded, 1.5–4 mm wide, apex trigonous, subulate. |
Inflorescences | spikelet clusters 4–6, widely spaced, loose, broadly to narrowly turbinate, paniculate, branches capillary, ultimate branches with 1 or 2 spikelets; leafy bracts exceeding proximal clusters, setaceous. |
spikelet clusters (2–)3–5, compact, proximalmost widely spaced, turbinate to ovoid; peduncles ascending; branches ascending to spreading; leaf bracts exceeding proximalmost clusters, exceeded by distal cluster. |
Spikelets | solitary or in 2s, brown, ovoid, 2.5–3.5 mm; fertile scales ovate, 1.5–2.2 mm, apex acute, apiculate. |
deep redbrown to nearly black, ovoid, 3–4 mm, apex acute; fertile scales ovate, 2.5–3 mm, apex acute, midrib included or shortexcurrent. |
Flowers | perianth bristles 6, reaching tubercle base or slightly beyond, antrorsely barbellate. |
perianth bristles 6, some short, some extending to or nearly to tubercle base, antrorsely barbellate. |
Fruits | 2–3 per spikelet, 1.5–1.6(–1.8) mm; body brown or greenish, obovoid, lenticular, 1.1–1.2(–1.3) × 0.7–1 mm, margins narrow, distinct, sharp, flowing to tubercle; surfaces finely transversely wavyrugulose, intervals of fine, nearly isodiametric or vertical-rectangular pitlike alveolae; tubercle lowtriangular, entire, 0.3–0.4 mm. |
2–3 per spikelet, 2–2.1 mm; body pale yellowbrown, lenticular, broadly ellipsoidobovoid, 1.3–1.6 × 1–1.2 mm; surfaces transversely irregularly rugulose, intervals with rows of vertical, narrowly rectangular alveolae; tubercle evenly or concavely triangular, 0.5–0.6(–0.7) mm. |
Rhynchospora decurrens |
Rhynchospora kunthii |
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Phenology | Fruiting late spring–summer. | Fruiting late spring–summer. |
Habitat | Sandy alluvium of swamp forests and environs | Marsh meadows, seeps, boggy sites |
Elevation | 0–100 m (0–300 ft) | 1000–3500 m (3300–11500 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC |
CA; Mexico; South America (Colombia) |
Discussion | Rhynchospora decurrens superficially resembles R. mixta, with which it is often associated in swamp forests. Its narrower fruit bodies with less distinct transverse rugosity; the smaller, more numerous rows of finer, pitlike alveolae; and its broader, lower tubercles with non-setose edges all comprise consistent differences. The name decurrens is apt, calling attention to the narrow, wirelike pale margins that extend from tubercle base to near the base of the fruit body. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 23, p. 226. | FNA vol. 23, p. 225. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Phaeocephalum decurrens | R. schaffneri |
Name authority | Chapman: Fl. South. U.S., 525. (1860) | Nees ex Kunth: Enum. Pl. 2: 296. (1837) |
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