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inundated beakrush, narrow-fruit beaksedge, narrowfruit horned beaksedge

swampforest beaksedge

Habit Plants perennial, clonal, 50–100 cm; rhizomes slender, scaly, to 2 mm thick. Plants perennial, cespitose, to 100 cm; rhizomes sometimes produced, short, not stoloniferous.
Culms

stiffly erect, leafy, triangular, multiribbed.

lax, erect to ascending-excurved, ± terete, leafy, slender, soft.

Leaves

erect, distal ones overtopping inflorescence;

principal blades flat proximally, trigonous distally, 3–10 mm wide, apex attenuate.

exceeded by inflorescence;

blades erect or ascending, linear, proximally flat, 2–4 mm wide, apex trigonous, subulate, tapering.

Inflorescences

terminal and axillary, clusters of corymbs (1–)2–3, open, spikelet clusters loose;

bracteal leaves mostly overtopping corymbs.

spikelet clusters 4–6, widely spaced, loose, broadly to narrowly turbinate, paniculate, branches capillary, ultimate branches with 1 or 2 spikelets; leafy bracts exceeding proximal clusters, setaceous.

Spikelets

pale redbrown, narrowly lanceoloid, (9–)11–14 mm, apex acuminate;

fertile scales lanceolate, 9–13 mm, apex acuminate, midrib shortexcurrent or not.

solitary or in 2s, brown, ovoid, 2.5–3.5 mm;

fertile scales ovate, 1.5–2.2 mm, apex acute, apiculate.

Flowers

perianth bristles 5–6, extending at least 5 mm beyond tubercle base, antrorsely barbellate.

perianth bristles 6, reaching tubercle base or slightly beyond, antrorsely barbellate.

Fruits

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.

2–3 per spikelet, 1.5–1.6(–1.8) mm;

body brown or greenish, obovoid, lenticular, 1.1–1.2(–1.3) × 0.7–1 mm, margins narrow, distinct, sharp, flowing to tubercle;

surfaces finely transversely wavyrugulose, intervals of fine, nearly isodiametric or vertical-rectangular pitlike alveolae;

tubercle lowtriangular, entire, 0.3–0.4 mm.

Rhynchospora inundata

Rhynchospora decurrens

Phenology Fruiting summer–fall. Fruiting late spring–summer.
Habitat Emergent in shallows of savanna ponds, interdunal pools Sandy alluvium of swamp forests and environs
Elevation 0–100 m (0–300 ft) 0–100 m (0–300 ft)
Distribution
from FNA
AL; DE; FL; GA; LA; MA; MD; MS; NC; NJ; NY; RI; SC; VA
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MS; NC; SC
[BONAP county map]
Discussion

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.)

Rhynchospora decurrens superficially resembles R. mixta, with which it is often associated in swamp forests. Its narrower fruit bodies with less distinct transverse rugosity; the smaller, more numerous rows of finer, pitlike alveolae; and its broader, lower tubercles with non-setose edges all comprise consistent differences. The name decurrens is apt, calling attention to the narrow, wirelike pale margins that extend from tubercle base to near the base of the fruit body.

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

Source FNA vol. 23, p. 208. FNA vol. 23, p. 226.
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. 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. 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. 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 Ceratoschoenus macrostachyus var. inundatus, R. macrostachya var. inundata Phaeocephalum decurrens
Name authority (Oakes) Fernald: Rhodora 20: 139. (1918) Chapman: Fl. South. U.S., 525. (1860)
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