Juncus tenuis is a perennial herb; stems 1 to 6 dm long, 1 to 2 mm in diameter, loosely cespitose. Leaves basal, numerous and crowded, blades variable in length, 7 to 30 cm long, 1 to 1.3 mm wide, sheaths loose with wide hyaline margins prolonged into white scarious auricles up to 5 mm long. Flowers (3-) numerous, borne singly on 1 side of rachis, in relatively compact dichasial cymes 1 to 7 cm long, forming less than 1/3 of plant, bracts 2 to 3, foliaceous, usually far exceeding inflorescence, each flower subtended by 2 bracteoles, these hyaline, triangular-ovate; perianth parts greenish, lanceolate, 3 to 4.5 mm long, apex long-acuminate, outer ones slightly reflexed at apex, inner ones with wide hyaline margins below; stamens 6, 1/2 as long as perianth; anthers shorter than filaments. Capsules reddish brown, 1-celled, broadly ovoid, thin-walled, slightly beaked, 2/3 to rarely scarcely shorter than perianth. Seeds pale brown, oblong, 0.3 to 0.4 mm long, slightly apiculate at both ends (Wagner et al. 1999, in PIER 2007).
Juncus tenuis is found naturalised in Hawaii usually in wet sites along trails, disturbed places, and pastures at altitudes of 700 to 2000 meters (Wagner et al. 1999, in PIER 2007).
Compiler: IUCN SSC Invasive Species Specialist Group (ISSG) with support from the EU-funded South Atlantic Invasive Species project, coordinated by the Royal Society for the Protection of Birds (RSPB)
Publication date: 2010-08-16
Recommended citation: Global Invasive Species Database (2020) Species profile: Juncus tenuis. Downloaded from http://www.iucngisd.org/gisd/speciesname/Juncus+tenuis on 25-11-2020.