Rhynchospora inundata
Rhynchospora megalocarpa
inundated beakrush, narrow-fruit beaksedge, narrowfruit horned beaksedge
sandyfield beaksedge
stiffly erect, leafy, triangular, multiribbed.
erect to arching, leafy, trigonous, slender, firm.
erect, distal ones overtopping inflorescence;
principal blades flat proximally, trigonous distally, 3–10 mm wide, apex attenuate.
overtopped by culms;
blades linear, proximally flat, 3–7 mm wide, apex trigonous, subulate, tapering.
terminal and axillary, clusters of corymbs (1–)2–3, open, spikelet clusters loose;
bracteal leaves mostly overtopping corymbs.
spikelet clusters 2–6, sparse, widely spaced, turbinate;
peduncles and branches ascending; leafy bracts exceeding proximal clusters.
pale redbrown, narrowly lanceoloid, (9–)11–14 mm, apex acuminate;
fertile scales lanceolate, 9–13 mm, apex acuminate, midrib shortexcurrent or not.
light redbrown, ovoid to ellipsoid, (4–)5–8(–9) mm, apex acute or acuminate;
fertile scales ovate, (5.5–)6–6.5(–7) mm, midrib included or shortexcurrent.
perianth bristles 5–6, extending at least 5 mm beyond tubercle base, antrorsely barbellate.
perianth bristles 6(–8), mostly reaching from fruit midbody to tubercle base, antrorsely barbellate.
1–2 per spikelet, 15–20 mm;
body stipitate, obovoid to oblong, compressed, 4–5 × 2–3 mm, margins thick;
surfaces concave, horizontally finely striate, minutely cancellate;
tubercle stoutbased, grooved, subulate, 10–15 mm, setulose.
1–2 per spikelet, (3.5–)4–5 mm;
body dark brown to mahogany or nearly black, broadly obovoid, tumid, nearly smooth, buttressed to tubercle;
tubercle lowconic, rimmed, 0.7(–1) mm, apex apiculate.
Rhynchospora inundata
Rhynchospora megalocarpa
Rhynchospora inundata is largely confined to lower Coastal Plain terraces, mostly along the present coast. Typical plants have narrow fruit bodies and narrow inflorescences of sparse clusters, well overtopped by leaves and erect leafy bracts. By contrast, plants of R. careyana have broader fruits, shorter perianths, and larger, broader inflorescences that overtop most or all leaves and bracts. In general, plants of R. careyana are more robust and grow in more acid sites than those of R. inundata. Southward in the Atlantic Coastal and Gulf Coastal plains are broad areas of ecotone where the two species intergrade.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The perianth in Rhynchospora megalocarpa is unusual. The receptacular joint is stubby, bearing staggered cycles of bristles that vary extremely in length and number—on a par with R. alba, R. baldwinii, and R. macra in numbers of bristles. The greatest extreme is twelve, the fewest as low as two; usually if the number is low, the remaining sites for bristles will be dark-colored nubbins.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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