Juncus densiflorus Kunth

• Authority

  Balslev, Henrik. 1996. Juncaceae. Fl. Neotrop. Monogr. 68: 1-167. (Published by NYBG Press)

• Family

  Juncaceae

• Scientific Name

  Juncus densiflorus Kunth

• Type

  Type. Venezuela.  In ripa fluminis Atabapi, juxta cataractam Guarinuma (Missiones del Alto-Orinoco), Humboldt & Bonpland s.n. (holotype, P!, photo, MO!).

• Synonyms

  Juncus cyperinus Willd. ex Spreng., Juncus densiflorus var. cyperinus Buchenau, Juncus polycephalus Michx., Juncus pohlii Steud., Juncus densiflorus var. pohlii (Steud.) Buchenau

• Description

  Species Description - Perennial herbs, 65-135 cm tall. Rhizome horizontal, creeping, 3-8 mm diam., scales thin, scari-ose, not covering the rhizome, internodes 1.5-2 cm long. Culms erect, 2.5-5.5 mm diam., smooth or finely nodulated, sometimes with fine longitudinal striations but never ridged. Cataphylls conspicuous, 1-3 to each culm, all basal or upper ones rarely inserted up to 20 cm from the base, stramineous to brown, lower one 1-6 cm long, upper ones to 20 cm long with 4-6 mm long rudimentary acicular blade. Foliar leaves (1-)2(-3) spread along the culm, lower one 25-75 cm long, sheaths 7-16 cm long with scariose margins terminating in 2 rounded 2-4 mm long auricles, blades terete 2-4.5 mm diam., hollow with transverse septa 2-15 mm apart but not always nodulated on the outside, upper leaf often inserted above the middle of the culm and usually much smaller than the others, its blade sometimes being only 5 cm long. Inflorescence decompound, anthelate, up to 20 x 7 cm, or congested and sometimes only 3 x 2.5 cm, flower heads 7-45, globose, 7-15 mm diam., 20-40-flowered, stramineous, principal branches to 12 cm long and 1.5 mm diam. Lower inflorescence bract 3-13 cm long, resembling cauline leaves with short blade or the blade rudimentary to 5 mm long, distal bracts shorter, floral bracts <½ as long as the flowers. Tepals linear-lanceolate, subulate, rigid, outer tepals 3-4 mm long, longer than inner tepals, concave to V-shaped in x.s., inner tepals 2.5-3.5 mm long, flat. Stamens 3, 1.5-2 mm long; filaments filiform; anthers oblong, 0.4-0.8 mm, distinctly shorter than the filaments. Capsule ovoid, beaked, trigonous, l.9-2.7 mm (incl. beak) x 1.1-1.2 mm, about 1/3 shorter than the tepals, light brown, unilocular, dehiscing laterally, the carpels remaining connate at the beak. Seeds ellipsoid, apiculate, 0.4-0.5 x 0.15-0.2 mm, reticulate.

• Discussion

  Distribution and Ecology: Juncus densiflorus is distributed in the Andes from Venezuela to Colombia at elevations of 1500-2700 m, in the highlands of SE Brazil at elevations of 800-1600 m, and in the lowlands of Paraguay, Argentina, and Uruguay. A few collections have been made in the Guyana Highlands, and this is the only species of Juncaceae recorded from that area. It grows in humid places in marshes, swamps, and along creeks and streamlets below the timberline.

• Common Names

  junco, totorilla

• Distribution

  Colombia South America| Antioquia Colombia South America| Boyacá Colombia South America| Cauca Colombia South America| Cundinamarca Colombia South America| Huila Colombia South America| Norte de Santander Colombia South America| Putumayo Colombia South America| Santander Colombia South America| Valle Colombia South America| Venezuela South America| Bolívar Venezuela South America| Lara Venezuela South America| Mérida Venezuela South America| Brazil South America| Bahia Brazil South America| Goiás Brazil South America| Minas Gerais Brazil South America| Rio de Janeiro Brazil South America| São Paulo Brazil South America| Paraguay South America| Caazapá Paraguay South America| Central Paraguay South America|