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indianola beaksedge

threadleaf beaksedge

Habit Plants perennial, cespitose, to 100 cm; rhizomes absent. Plants perennial, cespitose, 30–80(–100) cm; rhizomes absent.
Culms

stiffly erect or ascending, leafy-based, triangular, multiribbed.

erect or excurved, mostly filiform, leafy proximal to midculm, obtuse-angled to subterete, wiry.

Leaves

ascending or erect, crowded toward culm base, shorter, more widely spaced distally, longest overtopping or equaling subtended inflorescences;

principal blades flat, trigonous distally, 4–6 mm wide, apex attenuate, trigonous.

overtopped by culm;

blades narrowly linear, proximally flat, 1–2 mm wide, distally tapering-triquetrous.

Inflorescences

terminal and axillary, compounds of fascicles, nearly umbellate;

clusters hemispheric to nearly capitate, 1.5–2 cm wide; 1 cluster nearly sessile, others on slender rays to 7 cm, sometimes penultimate node with single cluster on peduncle 7–12 cm.

spikelet clusters 2–3(–4), distant, narrowly turbinate to hemispheric, mostly shorter than subtending setaceous bract.

Spikelets

light redbrown, lanceoloid, 6–7 mm, apex acute;

fertile scales lance-ovate, 5 mm, apex acute to blunt, midrib shortexcurrent or not.

red-brown, lanceoloid, 2.5–3(–4) mm, apex acuminate;

fertile scale elliptic, 2–2.5 mm, acute, midrib excurrent as cusp or aristula.

Flowers

perianth bristles 6, overtopping tubercle base, antrorsely barbellate.

bristles 6, reaching tubercle tip or beyond, antrorsely barbellate, base setose.

Fruits

1 per spikelet, (5.5–)6–7 mm;

body obovoid, 3–4 × 2–2.5 mm, margins thick, crimped, surfaces level or concave, minutely pebbled;

tubercle narrowly conic, 2grooved, 3–4 mm, base blunt, stout, capping fruit apex, tip barely exserted.

2–4 per spikelet, 1.5–1.7 mm, on setose pedicellar joint 0.2 mm, body with faces red-brown with pale glassy center, decurrent tubercle base;

surfaces smooth;

turbercle concavely triangular, 0.4–0.6 mm, setulose-ciliate.

Rhynchospora indianolensis

Rhynchospora filifolia

Phenology Fruiting early summer–fall. Fruiting summer–fall.
Habitat Silty shallows of pools, prairie swales, ditches Sands and peats of bogs, pineland pond shores, seeps, and low savannas in pinelands
Elevation 0–100 m (0–300 ft) 0–300 m (0–1000 ft)
Distribution
from FNA
TX
[BONAP county map]
from FNA
AL; DE; FL; GA; LA; MD; MS; NC; NJ; SC; TX; VA; Central America; South America; West Indies (Cuba)
[BONAP county map]
Discussion

Rhynchospora indianolensis was considered by G. Kükenthal to be closely related to, if not the same as, the Cuban R. scutellata Grisebach but with fruit of different dimensions and sculpture. W. W. Thomas (1984) believed the two to be conspecific.

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

On the acidic, sphagnous substrates shaded by Taxodium ascendens, Nyssa biflora, and Ilex myrtifolia stands in western Florida and southern Alabama, culms of Rhynchospora filifolia reach their greatest length and are lax, leaning on other vegetation, and produce increasingly more distant clusters of spikelets that are of a paler color than is usual for the species. In fact, R. filifolia presents the greatest morphologic spectrum for its complex of species, a complex best held together by the uniformity of its fruits.

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

Source FNA vol. 23, p. 207. 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. 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. 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. 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 filifolium
Name authority Small: Fl. S.E. U.S., 193, 1327. (1903) A. Gray: Ann. Lyceum Nat. Hist. New York 3: 366. (1836)
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