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flatfruit beaksedge

Habit Plants perennial, cespitose, 70–100(–150) cm; rhizomes absent. Plants perennial, densely cespitose, knottybased, 20–40 cm; rhizomes absent.
Culms

erect to ascending, leafiest at base, triangular, slender, somewhat stiff.

leafy at base, filiform, wiry.

Leaves

exceeded by culm;

basal blades crowded, spreadingexcurved, distal ascending, linear, proximally flat, 3–5 mm wide, apex trigonous, shortsubulate.

blades filiform, nearly reaching inflorescence tip or much shorter, to 0.3 mm thick, apex tapering.

Inflorescences

spikelet clusters 3–5, compact, the proximalmost widely spaced, turbinate or lobed to hemispheric; leafy bracts setaceous, mostly overtopping clusters.

spikelet clusters mostly 2–6, simple or reduced to 1 spikelet, often with 2 capillary branches, one divaricate or reflexed, 1 ascending; leafy bracts single per cluster, filiform, setaceous, with clusters appearing lateral to bracts.

Spikelets

redbrown, broadly ovoid, 3–3.5(–4) mm, apex acuminate;

fertile scales broadly ovate to ± orbiculate, 2–2.5(–3) mm, apex rounded to notched, midrib included or shortexcurrent.

pale redbrown, ellipsoidlanceoloid, 5–6(–8) mm, apex acute to acuminate;

fertile scales narrowly ovate, 3–5(–6) mm, apex acute, midrib included or shortexcurrent.

Flowers

perianth bristles 6, reaching from fruit midbody to tubercle, antrorsely barbellate.

perianth bristles 6, not reaching past fruit midbody, stubby, plumose to near tip.

Fruits

1–2 per spikelet, (2–)2.5–2.8(–3) mm;

body brownish, broadly obovoid to nearly orbicular, 1.5–2 × 1.5–2 mm;

surfaces strongly transversely wavyrugose, intervals rows of vertical, rectangular alveolae;

tubercle conic-subulate, basal rim flaring above short neck on achene.

3–8 per spikelet, 2–2.5 mm;

body light brown to brown, ellipsoid-obovoid, tumidly lenticular, 1.5–2 × 1.6–1.7 mm;

surfaces faintly, interruptedly crossrugulose, apically indented under tubercle;

tubercle lowconic, 0.5 mm, base flaring, circular.

Rhynchospora compressa

Rhynchospora breviseta

Phenology Fruiting spring–fall. Fruiting spring–summer.
Habitat Moist sands and peats of pine flatwoods, bog margins, savannas Moist to wet sands or peats of bogs, depressions in savannas, open pinelands, pond shores
Elevation 0–100 m (0–300 ft) 0–200 m (0–700 ft)
Distribution
from FNA
AL; FL; GA; LA; MS; SC
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC; VA; West Indies
Discussion

Rhynchospora compressa is very closely akin to R. recognita and even coarser; inflorescence clusters are about as bristly and fertile scales blunter than those in R. recognita. It is less inclined to have an excurrent midrib, and the fruit is flatter. Both species often produce sterile spikelets, sometimes comprising an entire inflorescence.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Rhynchospora breviseta is sympatric with R. oligantha over much of its range; intergrades have not been seen.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 23. FNA vol. 23.
Parent taxa Cyperaceae > Rhynchospora Cyperaceae > Rhynchospora
Sibling taxa
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. 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. 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. 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
Synonyms Phaeocephalum compressum, R. cymosa var. compressa R. oligantha var. breviseta
Name authority J. Carey ex Chapman: Fl. South. U.S., 525. (1860) (Gale) Channell: Rhodora 58: 336. (1956)
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