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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
from FNA
AL; AR; FL; GA; LA; MS; NC; OK; SC; TN; TX; VA
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[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC; TX
[WildflowerSearch map]
[BONAP county map]
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
R. alba, R. baldwinii, R. brachychaeta, R. breviseta, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. fusca, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. latifolia, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. mixta, R. nitens, R. nivea, R. odorata, R. oligantha, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. pusilla, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
R. alba, R. baldwinii, R. brachychaeta, R. breviseta, R. caduca, R. californica, R. capillacea, R. capitellata, R. careyana, R. cephalantha, R. chalarocephala, R. chapmanii, R. ciliaris, R. colorata, R. compressa, R. corniculata, R. crinipes, R. curtissii, R. debilis, R. decurrens, R. divergens, R. elliottii, R. eximia, R. fascicularis, R. fernaldii, R. filifolia, R. floridensis, R. fusca, R. globularis, R. glomerata, R. gracilenta, R. grayi, R. harperi, R. harveyi, R. indianolensis, R. inexpansa, R. inundata, R. knieskernii, R. kunthii, R. latifolia, R. macra, R. macrostachya, R. megalocarpa, R. megaplumosa, R. microcarpa, R. microcephala, R. miliacea, R. nitens, R. nivea, R. odorata, R. oligantha, R. pallida, R. perplexa, R. pineticola, R. pleiantha, R. plumosa, R. punctata, R. pusilla, R. rariflora, R. recognita, R. scirpoides, R. solitaria, R. stenophylla, R. thornei, R. torreyana, R. tracyi, R. wrightiana
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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