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flatfruit beaksedge

Curtiss' beaksedge

Habit Plants perennial, cespitose, 70–100(–150) cm; rhizomes absent. Plants perennial, densely cespitose, 10–30 cm; rhizomes absent.
Culms

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

lax, erect to excurved, leafy toward base, filiform.

Leaves

exceeded by culm;

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

overtopped by scape;

blades filiform, distally flattened, channeled, tapering, to 1 mm wide, margins strongly involute, apex blunt.

Inflorescences

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

spikelet clusters 1–3, laterals widely spaced, all narrowly turbinate, ellipsoid, or ovoid; leafy bracts setaceous, overtopping proximal clusters, often overtopped by terminal ones.

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.

erect or ascending, redbrown, lanciform, mostly 4.5–5 mm, apex acute;

fertile scales lanceolate, (3–)4–4.5 mm, apex acute, apiculate.

Flowers

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

perianth absent.

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.

2–3(–5) per spikelet;

stipe and receptacle 0.1–0.2(–0.3) mm, setose;

body brown with pale glassy center, narrowly obovoidellipsoid, lenticular, 1.2–1.5 mm, margins narrow, flowing to tubercle;

surfaces very finely lined longitudinally, transversely with wavy lines of tiny pits;

tubercle narrowly triangular or slightly concavesided, flattened, 0.7–1.2(–1.5) mm.

Rhynchospora compressa

Rhynchospora curtissii

Phenology Fruiting spring–fall. Fruiting summer–fall.
Habitat Moist sands and peats of pine flatwoods, bog margins, savannas Sands and peats of bogs, pineland pond shores, seeps, and low moist savannas
Elevation 0–100 m (0–300 ft) 0–100 m (0–300 ft)
Distribution
from FNA
AL; FL; GA; LA; MS; SC
[BONAP county map]
from FNA
AL; FL; MS
[BONAP county map]
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.)

Source FNA vol. 23. FNA vol. 23, p. 234.
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. 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. 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 Phaeocephalum curtissii, R. filifolia var. ellipsoidea
Name authority J. Carey ex Chapman: Fl. South. U.S., 525. (1860) Britton: in J. K. Small, Fl. S.E. U.S., 195, 1327. (1903)
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