Juncus effusus L.
Family
Juncaceae
Synonyms
Juncus communis E. Mey., Juncus sundaicus RidI.
Vernacular Names
| English | Soft rush, common rush, mat rush. |
| Indonesia |
Sumpu, udulan (Javanese). |
| Philippines | Sudsud (lgorot), pingot, balili (Bontoc). |
| Vietnam |
C[aa]y b[aas]c, b[aas]c d[ef]n, d[aw]ng t[aa]m th[ar]o. |
| French | Jonc à lier, jonc épars. |
Geographical Distributions
Juncus effusus is widely distributed in the temperate zones of the world, especially in the northern hemisphere, and the mountainous parts of the tropics, but it is not found in Australia. It is native to Southeast Asia where it is found in Malaysia (Sabah, Sarawak), Indonesia (Aceh, Java, Kalimantan), the Philippines (from Luzon to Mindanao), New Guinea, northern Thailand and Vietnam. J. effusus is cultivated in Japan, China, Taiwan, the Philippines and northern Vietnam. It is sometimes considered a weed, for instance in pastures.
Description
Juncus effusus is a semi-aquatic, sedge-like, densely tufted, erect, hairless, rhizomatous and perennial herb that can grow 40-120 cm tall. Its rhizome is tough, creeping horizontal, short, very short-jointed and scaly. The stem is cylindrical with continuous pith, measures 1-3 mm thick, and not or hardly ribbed (when dried, very closely-set faint longitudinal ribs are visible).
The leaves are represented by basal scale-like sheaths. There are several sheaths which embrace the stem, red-brown, bladeless, obtuse, measure 5-12 cm long and often with a deciduous awn at the apex.
The inflorescence is a pseudolateral, dense or lax cymose panicle and usually many-flowered and measures 1-10(-15) cm long. The bract of the inflorescence is erect, cylindrical, acute at apex, simulates a continuation of the stem and overtops the inflorescence by 14-25 cm. The flowers are partly sessile. They are partly stalked with petiole 8 mm long. The 2 thin floral bracts are very close together, ovate and measure about 0.7-0.8 mm long. There are 6 perianth segments which are subequal, narrowly ovate-Iance-shaped, measure 2-3.5 mm long, firm with transparent thin margins, with very acute apex and yellowish to pale green. There are 3(-6) stamens which are much shorter than the tepals, with anthers scarcely 1 mm long and are equal or shorter than the filaments. The pistil is with a sessile ovary and very short style. The 3 slender stigmas are long and erect.
The fruit is a 3-valved capsule, three-angled-oblong, measures 2-3 mm long, brown and with numerous seeds. The seed is broadly ellipsoid, measures about 0.4-0.5 mm long, apiculate and finely reticulate.
Ecology / Cultivation
Juncus effusus is found in wet locations, such as pools, swamps, lake borders and river banks. In Southeast Asia, where it occurs at 1200-3000 m altitude, it is locally abundant, but generally rare. The base and optimum temperatures for tillering of J. effusus var. decipiens have been found to be about 3°C and 16°C respectively, with adequate tillering occurring in temperature range of 11-21°C. In cultivation, J. effusus prefers fertile clay, clay-loam or loam soils with pH 6. The rhizomes are less tolerant of low oxygen conditions than those of Schoenoplectus lacustris (L.) Palla and Typha spp. In Europe, natural stands of J. effusus are often indicative of disturbed, nutrient-rich soils which are low in lime.
Line Drawing / Photograph
References
- Plant Resources of South-East Asia No.17: Fibre plants.
