Rhynchospora gracilenta |
Rhynchospora cephalantha |
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slender beaksedge |
bunched beaksedge |
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Habit | Plants perennial, densely cespitose or solitary, 10–100 cm; rhizomes absent. | Plants perennial, cespitose, 40–100(–150) cm; rhizomes absent. |
Culms | mostly lax, ascending to leaningexcurved, leafy, linear to filiform, terete. |
arching, leafy, obscurely and convexly trigonous, multi-ribbed, slender to stoutish. |
Leaves | shorter than culm; blades ascending, filiform to narrowly linear, proximally flat, 0.5–1.5(–2.5) mm wide, margins distally strongly involute, apex trigonous, tapering. |
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Inflorescences | spikelet clusters 1–3(–4), proximalmost distant, dense to sparse, narrowly turbinate to hemispheric; peduncles and branches ascending; leafy bracts linearsetaceous, mostly overtopping clusters. |
spikelet clusters 3–several, widely spaced, often equidistant, mostly hemispheric to globose, occasionally lobed, 1–2 cm thick; bracteal leaves much exceeding subtended inflorescence. |
Spikelets | redbrown, ovoid to lanceoloid, (3.5–)4–5 mm, apex acute; fertile scales ovate, 3–4.5 mm, apex acute, mucronate to awnedcuspidate. |
dark red-brown to dark brown, lanceellipsoid to ellipsoid, 4–5(–6) mm, apex acute; fertile scales elliptic, 3–3.5(–4.5) mm, apex acute, midribs 3, laterals indistinct. |
Flowers | bristles 6, mostly reaching tip of tubercle or beyond, antrorsely barbellate. |
perianth bristles 6, reaching tubercle tip, retrorsely (rarely antrorsely) barbellate. |
Fruits | 1–3 per spikelet, (2.5–)3–3.5(–4.1) mm; body dark brown with small pale center, lenticular, broadly ellipsoid to suborbicular, 1.3–2.1 × 1.3–1.5 mm, smooth, margins narrow, flowing into tubercle; tubercle triangular-subulate, compressed, mostly 1.5–2 mm. |
1(–2) per spikelet, 3.5–4(–4.2) mm; body brown with pale center, obovoid distal to stipe, lenticular, 2–2.3 × 1–1.5(–2) mm; tubercle triangular-subulate, (1–)1.5–2 mm, at least 0.5 mm wide at base. |
Principal | leaves overtopped by culm; blades linear, flat proximally, 1.5–3 mm wide, apex tapering, trigonous. |
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Rhynchospora gracilenta |
Rhynchospora cephalantha |
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Phenology | Fruiting late spring–fall. | Fruiting summer–fall. |
Habitat | Moist to wet sandy peaty substrates in ditches, bogs, seeps, wet savannas, barrens, and flatwoods | Sandy silts, sands, and peats of shores, boggy streams, seeps, savannas, and savanna bogs |
Elevation | 0–400 m (0–1300 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; AR; DE; FL; GA; LA; MD; MS; NC; NJ; OK; PA; SC; TN; TX; VA; Central America; West Indies (Cuba)
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AL; DE; FL; GA; LA; MD; MS; NC; NJ; NY; SC; TX; VA
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Discussion | Through the southern coastal plain are widerleaved examples of Rhynchospora gracilenta that are sparingly cespitose to solitary-stemmed, often with but a single terminal inflorescence with dense clusters of spikelets (var. diversifolia). That would be a tenable designation were it not for the large numbers of populations with intermediate habit. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
North American plants referred to Rhynchospora axillaris (Lamarck) Britton [Phaeocephala axillare (Lamarck) House by N. L. Britton and A. Brown (1913) and J. K. Small (1933)] are actually R. cephalantha. A photograph of the type specimen of Schoenus axillaris Lamarck (from P) reveals what appears to be an immature top of S. glomeratus [R. glomerata (Linnaeus) Vahl]. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 236. | FNA vol. 23, p. 212. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Phaeocephalum gracilentum, R. drummondiana, R. gracilenta var. diversifolia, R. trichophylla | R. cephalantha var. attenuata, R. cephalantha var. pleiocephala |
Name authority | A. Gray: Ann. Lyceum Nat. Hist. New York 3: 216. (1835) | A. Gray: Ann. Lyceum Nat. Hist. New York 3: 218. (1835) |
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