Juncus diffusissimus Buckley
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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. North Western Texas, Buckley s.n. (lectotype, PH!, here selected, photo AAU!; possible isotype, NY).
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Description
Species Description - Perennial, loosely cespitose, herbs, 25-70 cm tall. Rhizome densely branching, clustered, 3-4 mm diam. Culms erect, 1-2 mm diam., terete, smooth. Cataphylls absent or inconspicuous. Foliar leaves 13 basal and 2-3 cauline to each culm, 10-35 cm long; sheaths 1-8 cm long, with scariose margins terminating in two 3 mm long, rounded auricles; blade ca. 1-3 mm diam., straight or sometimes ascending, round to elliptic in x.s., septate. Inflorescence up to 4 x branched, 8-20 cm long and 415 cm wide with spreading branches, flower heads up to 100, in anthelate arrangement, each head 2-5(-10)-flowered, usually conical in outline, the ultimate head bearing branches ca. 0.2 mm diam. Lower inflorescence bract inconspicuous and usually much shorter than the inflorescence, resembling a small cauline leaf, distal bracts scalelike, scariose, floral bracts scariose, ca. 1 mm long. Tepals equal, lanceolate to linear, acute but not acuminate, stramineous and reddish tinged in the centerline, 2.5-3 mm long, outer tepals concave, inner tepals flat. Stamens 3, 1-1.5 mm long; anthers linear ca. as long as the filament. Capsule linear to lanceolate, acute and short apiculate, trigonous, 5-6 x 0.7-1 mm and about 2 x as long the tepals, light golden brown, unilocular. Seeds ellipsoid, apiculate, ca. 0.4 x 0.2 mm, reticulate, yellowish brown.
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Discussion
Juncus diffusissimus is easily recognised by the combination of its profusely branched inflorescence with spreading branches and its linear, trigonous, golden brown capsules that are about twice as long as the tepals and therefore protrude conspicuously from the tepals at the fruiting stage.
Distribution and Ecology: Juncus diffusissimus is distributed in SE and C U.S.A. with a northern limit from Virginia to Indiana and a southern limit from Florida to Texas, where it grows in wet soil and mud. Its stray occurrence in Peru, documented here for the first time and only by a single collection, is separated from its main area of distribution by 3000-4000 km; it can be explained only by random long-distance dispersal caused by humans or migrating birds. In Peru its habitat is aquatic, according to the herbarium label.
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Distribution
Peru South America| Lambayeque Peru South America|