Rhynchospora caduca |
Rhynchospora mixta |
|
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anglestem beaksedge |
mingled beaksedge |
|
Habit | Plants perennial, cespitose, 70–150 cm; rhizomes often present, short, scaly. | Plants perennial, cespitose, 80–100 cm; rhizomes stoloniferous, often elongate, slender, to 1 dm or more. |
Culms | erect or ascending, leafy, trigonous. |
|
Leaves | exceeded by culm; blades linear, proximally 4–7 mm wide, apex trigonous, tapering. |
exceeded by culm; blades lax, linear, proximally flat, 3–5 mm wide, apex abruptly narrowed, trigonous, subulate. |
Inflorescences | terminal and axillary; clusters 3–6, mostly dense, narrowly to broadly turbinate, branches ascending; leafy bracts exceeeding proximalmost inflorescences. |
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 | rich brown, ovoid, (3–)4–5 mm, apex acuminate; fertile scales ovate, 2.5–3.5 mm, apex acuminate, midrib included or shortexcurrent. |
lanceovoid, 3–4(–6) mm, apex acute to acuminate; fertile scales elliptic, 2.5 mm, apex acute, midrib forming mucro or awn. |
Flowers | perianth bristles mostly 6, exceeding tubercle tip. |
perianth bristles 6, overtopping tubercle, antrorsely barbellate. |
Fruits | mostly 3–4 per spikelet, 2–2.2 mm; body brown on short pedicellar (to 0.3 mm) stalk, broadly obovoid, lenticular, 1.3–1.5 × 1–1.5 mm, surfaces transversely rugulose, vertically finely striate and rectangularalveolate; tubercle compressed, triangular acuminate, 0.5–0.8 mm, edges setulose. |
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 caduca |
Rhynchospora mixta |
|
Phenology | Fruiting summer–fall. | Fruiting summer–fall. |
Habitat | Low meadows, clearings, marshes, marsh borders, seeps, bog moats, savannas, ditches, pine flatwoods, swamps | Sandy silts of swamp forests and environs |
Elevation | 0–400 m (0–1300 ft) | 0–200 m (0–700 ft) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TN; TX; VA
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AL; FL; GA; LA; MS; NC; SC; TX
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Discussion | Rhynchospora caduca has its closest relationships with the even more robust R. odorata Grisebach, on the one hand, and the swampinhabiting, more slender, and rhizomatous R. mixta Britton ex Small, on the other. Intergrades with R. odorata appear in Alabama and northwest Florida; intergrades with R. mixta appear where ranges overlap in both the Atlantic and Gulf coastal plains. (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. 223. | FNA vol. 23, p. 224. |
Parent taxa | Cyperaceae > Rhynchospora | Cyperaceae > Rhynchospora |
Sibling taxa | ||
Synonyms | Phaeocephalum caducum, R. patula | Phaeocephalum proliferum, R. prolifera |
Name authority | Elliott: Sketch Bot. S. Carolina 1: 62. (1816) | Britton: in J. K. Small, Fl. S.E. U.S., 197, 1328. (1903) |
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