Juncus

• Authority

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

• Family

  Juncaceae

• Scientific Name

  Juncus L.

• Type

  Type. Juncus inflexus Linnaeus, lectotype, selected by Novikov (1976), not J. acutus Linnaeus, selected by Coville (1913).

• Synonyms

  Cephaloxys Desv., Juncastrum Fourr.

• Description

  Genus Description - Annual or perennial, rhizomatous, glabrous herbs. Culms usually erect, rarely procumbent or ascending. Leaves alternate, scale-like on the rhizomes, cataphyllous (i.e., with reduced blades) and/or foliar on the base of the culm, and bracteous in the inflorescence. Sheaths open, usually conspicuously auriculate at the junction to the blade. Blade linear with varying x.s.: flat with raised margins and slightly channeled above, canaliculate, round to elliptic, or completely flat. Inflorescence compound and often decompound, cymose or racemose, often anthelate. Inflorescence bracts decreasing in size from the base of the inflorescence upwards, the lower bract often conspicuously different from the remaining ones. Flowers bisexual, sometimes clasped by 2 bracteoles on the pedicel. Tepals equal or subequal, lanceolate, entire, persistent, stramineous or castaneous, sometimes light green. Stamens 3 or 6; filaments filiform or flat, sometimes widened at the base; anthers linear or oblong, obtuse. Ovary sessile. Stigmas 3, filiform, twining, papillose. Capsule 1-locular, 3-septate, or 3-locular. Seeds many, ellipsoid, oblong or ovoid, smooth, rugose or sometimes with reticulate pattern, brown, yellowish, or castaneous. The name Juncus is derived from the Latin verb jungo (join, unite), probably referring to ancient use of these plants for binding things together.

• Discussion

  Taxonomic History of Juncus

  Since Linnaeus’ Species Plantarum (1753), the name Juncus has been stable in the botanical literature and an ever-increasing number of species has accumulated in the genus. Linnaeus (1753) described 15 species of Juncus; of these, three now belong in Luzula. Rostkov’s (1801) monograph of Juncus treated 52 species of which 13 were transferred to Luzula by A. P. de Candolle (1805), Prionium by E. Meyer (1822), and Rostkovia and Marsippospermum by Desvaux (1809). Laharpe (1825) treated 78 species of Juncus, Kunth (1841) 105 species, and Buchenau (1890, 1906) 176 and 207 species, respectively. Since Buchenau’s monographs there has been no treatment of the entire genus, but many new species have been described in regional works or revisions of sections of the genus.

• Distribution

  Juncus is a cosmopolitan genus of about 220 species, most of which occur in the north temperate region but with some proliferation in the temperate parts of the Southern Hemisphere. In the tropics the genus is absent in the lowlands but present at higher elevations, usually above 2000 m. The neotropical region has 41 species, tropical Africa has seven, and tropical Asia has four species of Juncus.