Rhynchospora decurrens |
Rhynchospora elliottii |
|
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swampforest beaksedge |
Elliott's beaksedge |
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Habit | Plants perennial, cespitose, to 100 cm; rhizomes sometimes produced, short, not stoloniferous. | Plants perennial, cespitose, 80–150 cm; rhizomes absent. |
Culms | lax, erect to ascending-excurved, ± terete, leafy, slender, soft. |
erect with arching tops, leafy, obscurely trigonous, slender. |
Leaves | exceeded by inflorescence; blades erect or ascending, linear, proximally flat, 2–4 mm wide, apex trigonous, subulate, tapering. |
overtopped by inflorescence; blades linear, proximally flat, 3–5 mm wide, apex trigonous, subulate, tapering. |
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 mostly 4–6, various in shape and crowding, narrowly to broadly turbinate; peduncles erect, branches slender, ascending; leafy bracts exceeding all but most distal clusters. |
Spikelets | solitary or in 2s, brown, ovoid, 2.5–3.5 mm; fertile scales ovate, 1.5–2.2 mm, apex acute, apiculate. |
redbrown, broadly ellipsoid, (1.5–)2–3(–3.5) mm, apex acute; fertile scales broadly ovate, 2–3 mm, midrib excurrent as apiculus or awn. |
Flowers | perianth bristles 6, reaching tubercle base or slightly beyond, antrorsely barbellate. |
perianth bristles 6, mostly spreading, usually exceeding tubercle, 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(–4) per spikelet, 1.5(–1.7) mm; body pale brown to brown, strongly flattened, obovoidorbicular, 1–1.2 × 0.8–1.1; surfaces transversely wavyrugose, intervals vertically striate with very narrowly rectangular alveolae; tubercle flat, triangular or concavely triangular, 0.3–0.5(–0.7) mm. |
Rhynchospora decurrens |
Rhynchospora elliottii |
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Phenology | Fruiting late spring–summer. | Fruiting late spring–fall or all year (south). |
Habitat | Sandy alluvium of swamp forests and environs | Sands and peats of bogs, shorelines, interdunal swales, savannas, and pine flatwoods |
Elevation | 0–100 m (0–300 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; FL; GA; LA; MS; NC; SC |
AL; FL; GA; LA; MS; NC; SC; TX |
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.) |
Rhynchospora elliottii is most likely to be confused in the field with its frequent associates R. microcarpa and R. perplexa. Most of the time it can be distinguished from both by its taller, coarser, broader-leaved habit and by its distinctly redder spikelets. Inspection of the fruit reveals the spreading character of the perianth bristles, these usually a length level with the tubercle tip or longer and giving the whole structure the appearance of an unengorged tick. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 226. | FNA vol. 23, p. 229. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Phaeocephalum decurrens | Phaeocephalum schoenoides, R. multiflora, R. schoenoides, Scirpus schoenoides |
Name authority | Chapman: Fl. South. U.S., 525. (1860) | A. Dietrich: Sp. Pl. 2: 69. (1833) |
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