Rhynchospora brachychaeta |
Rhynchospora mixta |
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West Indian beaksedge |
mingled beaksedge |
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Habit | Plants perennial, densely cespitose, 20–50 cm; rhizomes absent. | Plants perennial, cespitose, 80–100 cm; rhizomes stoloniferous, often elongate, slender, to 1 dm or more. |
Culms | erect to excurved, lax, filiform, leafy, ± terete. |
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Leaves | exceeded by culm, ascending; blades filiform, ± terete, margins strongly involute, apex trigonous, sulcate, tapering. |
exceeded by culm; blades lax, linear, proximally flat, 3–5 mm wide, apex abruptly narrowed, trigonous, subulate. |
Inflorescences | spikelet clusters mostly 2–3, sparse to dense, oblong to broadly or narrowly turbinate; leafy bracts setaceous, exceeding clusters. |
spikelet clusters 4–6, mostly widely spaced; peduncles erect or ascending, slender; branches capillary, divaricate, or widely spreading, to small clusters of 1–few spikelets; leafy bracts mostly exceeding clusters. |
Spikelets | pale redbrown, lanceoloid, 3–3.5 mm, apex acute; fertile scales mostly elliptic, 2–2.5 mm, apex acute, sometimes apiculate. |
lanceovoid, 3–4(–6) mm, apex acute to acuminate; fertile scales elliptic, 2.5 mm, apex acute, midrib forming mucro or awn. |
Flowers | bristles mere nubs or 1–2, to 0.3 mm. |
perianth bristles 6, overtopping tubercle, antrorsely barbellate. |
Fruits | mostly 2 per spikelet, 1.5–1.6 mm; body redbrown with pale center, lenticular, broadly obovoid to orbicular, margins pale, narrow, flowing to tubercle; surfaces smoothish, or faintly cancellate; tubercle flattened, triangularsubulate, 0.3–0.5 mm. |
mostly 2–4(–several) per spikelet, (1.5–)1.8–2(–2.1); body greenish or pale brown, broadly ellipsoid to narrowly obovoid, lenticular, 1.2–1.5 × 1–1.2 mm; surfaces transversely finely wavy-rugulose, intervals vertically striatealveolate, or alveolae isodiametric; tubercle flat, triangular-subulate, 0.5–0.6(–0.8) mm. |
Rhynchospora brachychaeta |
Rhynchospora mixta |
|
Phenology | Fruiting late spring–fall. | Fruiting summer–fall. |
Habitat | Moist sandy peaty substrates in savannas or savanna bog transition, ditches, and moist, disturbed areas | Sandy silts of swamp forests and environs |
Elevation | 0–200 m (0–700 ft) | |
Distribution |
AL; FL; MS; Central America; West Indies |
AL; FL; GA; LA; MS; NC; SC; TX
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Discussion | Rhynchospora brachychaeta is quite possibly adventive; most of its localities in the flora are in disturbed areas near the coast. It is similar to the widespread native R. chapmanii, from which it is distinguished by its more numerous spikelet clusters, the darker spikelets, the achene faces brown with pale centers (rather than pale with brown ends), and the relatively more developed perianth. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Some extremes of Rhynchospora caduca with more diffuse inflorescences are mistaken for R. mixta, particularly those in which ultimate inflorescence branches lead to solitary spikelets. In those rare instances one should find a somewhat larger spikelet and a broader fruit than is typical for R. mixta. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 23, p. 235. | FNA vol. 23, p. 224. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Phaeocephalum brachychaetum, R. blauneri, R. chapmanii, R. pallida, R. pallida | Phaeocephalum proliferum, R. prolifera |
Name authority | C. Wright: Anales Real Acad. Ci. Méd. Fís. Nat. Habana 8: 85. (1873) | Britton: in J. K. Small, Fl. S.E. U.S., 197, 1328. (1903) |
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