Juncus repens Michx.
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Authority
Balslev, Henrik. 1996. Juncaceae. Fl. Neotrop. Monogr. 68: 1-167. (Published by NYBG Press)
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Family
Juncaceae
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Scientific Name
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Type
Type. U.S.A. Carolina and Georgia (holotype, P!; isotype, P!; fragments, MO!, P!).
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Synonyms
Cephaloxys flabellata Desv., Juncus subincurvus Steud.
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Description
Species Description - Perennial heteromorphic herbs. One form is cespitose, 5-15 cm tall with 1 to several short, erect culms bearing l-4(-8) flower heads; another form is prostrate with creeping stems that root and produce leaf rosettes 5-10 cm apart; and a third form is floating with leaf rosettes evenly spaced along the stems. Rhizome absent in prostrate plants, weakly developed, densely branching, and 0.5-1.5 mm diam. in cespitose plants. Culms flattened, 0.8-2 mm diam., smooth, shorter than the rosette leaves, creeping and floating stems 1.5-2.5 mm diam. and up to 50 cm long with 5-10 cm long internodes. Foliar leaves in tufted rosettes, 2-15 x 0.1-0.4 cm, flat; sheaths 0.5-1.5 cm long, not clearly separated from the blades, margin scariose, terminating in two 0.5 mm long, rounded auricles. Inflorescence of 2-8 flower heads arranged in an anthela that overtops the leaves, flower heads conical to hemispherical, 7-13(-20) mm diam., 2-20-flowered. Lower inflorescence bract resembling basal leaves, distal ones shorter, floral bracts broadly lanceolate, mucronate, 1-2 mm long, bracteoles absent. Tepals unequal, green, sometimes reddish apically or throughout, outer tepals 2.8-4.2 mm long, concave, scariose toward the margin, inner tepals distinctly longer, (3.5-)4-5 mm, flat, subulate, with distinct, narrow, involute, scariose margins. Stamens 3, 2-3 mm long, opposite the outer tepals; filaments delicately filiform, hyaline; anthers 0.3-1 mm, first linear and as long as the filaments, after anthesis shrivelling to lh of filament length. Style ca. 0.2 mm long. Stigmas ca. 0.4 mm long. Capsule linear to lanceolate, apically truncate or 3-keeled and retuse, trigonous, 2.5-3.5 x 0.7-1.1 mm, as long as or longer than outer tepals but shorter than inner tepals, the base thin-walled and hyaline, the apex thicker and stramineous or golden brown, trilocular with central columellar placentation and ascending ovules. Seeds oblique, ovoid, apiculate, ca. 0.3 x 0.15 mm, finely rugose, castaneous or whitish, =100 per capsule.
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Discussion
The morphological variation and anatomy of Jun-cus repens were described in some detail by Holm (1899). Its growth is correlated to the nature of the habitat; when submerged it produces long shoots with long internodes and leaf rosettes at the nodes, and in shallow water its long shoots may root at the nodes. When growing above the water line it attains a tufted habit; intermediate forms are often found.
Distribution and Ecology: Juncus repens is distributed in the E U.S.A. from Delaware to Florida, Texas and Oklahoma, Tennessee, and Arkansas. Disjunct in lower California (Small, 1903), on Cuba in the W province of Piñar del Río and on Isla de Pinos, and in Tabasco in Mexico. It grows in muddy or sandy loam soils at the margins of fresh water and cypress gum ponds and lakes, in swamps and bogs, and often in pine woods or pine barrens. On Cuba it has been collected in dried-out stream beds.
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Distribution
Mexico North America| Tabasco Mexico North America| Cuba South America| Isla de Piños Cuba South America| Piñar del Río Cuba South America|