Juncus breviculmis Balslev
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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. Venezuela. Mérida: Páramo at Laguna de Mucubaji, nr. Apartaderos and San Rafael, 35 km NE of Mérida, 3800 m, 18 Oct 1953, Maguire 39428 (holotype, NY!).
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Description
Species Description - Perennial, soft, cespitose herbs, 8-40 cm tall. Rhizome densely and irregularly branching, ca. 2 mm diam. Culms erect, 1-20 cm long and always shorter than the leaves, 1-2.5 mm diam., terete, smooth or with small transverse nodules, sometimes branching in the axils of cauline leaves. Cataphylls absent or inconspicuous. Foliar leaves 1-2 basal and 0-2 cauline to each culm, 6-40 cm long; sheaths 1-6 cm long, scariose toward the margins and terminating in 2 rounded auricles 1-2.5 mm long; blades 1.5-2.5 mm diam., round in x.s. but usually flat in pressed specimens, conspicuously transverse-septate. Inflorescence a terminal head or a once to twice branched anthela to 7 x 10 cm with up to 7 heads; heads globose, 10 mm diam. and up to 40-flowered when single, or conical, 5 mm diam. and only 6-7-flowered in many-headed inflorescences. Lower inflorescence bract 4-20 cm long, resembling a cauline leaf, always conspicuously overtopping the inflorescence, sometimes straight, longer than the culm and appearing as a continuation of it except for being cross-septate, sheaths 1-5 cm long, blades 1-2.5 mm diam., floral bracts lanceolate, acuminate, 2-3 mm long, scariose. Tepals equal, 3-4 mm long, lanceolate, acute, brown to reddish with well-marked white scariose margins. Stamens 6, ca. 1.5 mm long; filaments filiform, whitish; anthers oblong, ca. 0.5 mm long, yellow. Capsule oblong to obovoid, slightly apiculate and trigonous, 2.3-3 x 1.3-1.6 mm, thin-walled, golden to dark brown. Seeds ellipsoid, apiculate, 0.4-0.5 x ca. 0.2 mm, reticulate, brown.
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Discussion
Juncus breviculmis may be recognised by its short culms which never lift the inflorescence above the tip of the foliar leaves. As a result of ecological modifications, the length of the culm and the degree of congestion of the inflorescence both vary considerably but in a correlated manner. Thus, small plants with culms 1-3 cm long usually have a quite congested inflorescence often consisting of a single 1 x 1 cm head terminating the culm, whereas taller plants with culms 15-20 cm long have more open inflorescences up to 7 x 10 cm with several heads, each bearing 6-7 flowers. All intermediates occur. At least one of the labels of the specimens cited above indicated that this species grows submerged, and therefore the morphological variation may reflect differences in water depth or, in the case of nonsubmerged plants, the amount of moisture in the soil and the lushness of the surrounding herb layer.
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Distribution
Juncus breviculmis is distributed in the N Andes from the province of Mérida in Venezuela to Cundinamarca in Colombia. It grows, sometimes submerged, in lakes and streams in the páramos at elevations of 3500-4100 m.
Colombia South America| Boyacá Colombia South America| Cundinamarca Colombia South America| Santander Colombia South America| Venezuela South America| Mérida Venezuela South America|