Articles

Conyza sumatrensis (Retz.) E.H. Walker

Conyza sumatrensis (Retz.) E.H. Walker

Family

Compositae

Synonyms

Erigeron sumatrensis Retz., Erigeron linifolius auct. non Willd.

Vernacular Names

Malaysia Chapa, sawi bulan, tembak-tembak hutan.
English Fleabane
Indonesia Jalantir, monyenyen (Sundanese), sembung (Javanese).
Vietnam C[us]c voi.

Geographical Distributions

C. sumatrensis originates from South America, but has at present a pantropical distribution. It has even spread as a weed to more temperate areas, e.g. in Europe.

Description

C. sumatrensis is a short-lived perennial, erect herb that grows up to 350 cm tall. It is strongly branched in the upper part.

Leaves are arranged alternate, simple, oblanceolate to linear-oblanceolate with a size of 3-12 cm x 0.3-3 cm and gradually tapering at base. The larger ones are sparsely coarsely dentate-serrate in the upper part while the smaller ones are often entire, sessile with grey hair on both sides. The stipules are absent.

Inflorescence is a small cylindrical head, 5-6 mm long and together arranged in a long leafy panicle with many-flowered but short peduncle.  The flowers are all tubular and they are about 4 mm long. The female flowers are marginal.  Petal is with 2-lobed apex, pale yellow to purplish and shortly exserted from the involucre. The flowers disk is bisexual or male, with narrowly funnel-shaped petal widening into 5 lobes and pale yellow in colour. There are 5 exserted stamens that form a tube. The 1-celled ovary is inferior with style having2 short and thick arms.

Fruit is small, compressed, ellipsoid achene, 1.5-2 mm long, with narrowed base and thickened margins with sparsely hairy. The pappus hairs are numerous, 1-2-seriate, 3-4 mm long, thin and toothed.

Seedling is with epigeal germination. The hypocotyl is about 1 mm long.  Cotyledons are subsessile and they are elliptical to ovate. The epicotyl is absent. 

Ecology / Cultivation

C. sumatrensis occurs gregariously in sunny or slightly shaded, dry or moist localities on a wide range of soils in regions with a weak or pronounced dry season. It can be found in grassland, roadsides, wasteland, fields, secondary forest, and rubber and tea plantations, from sea level up to over 3000 m altitude.

Line Drawing / Photograph

BOT00136

References

  1. Plant Resources of South-East Asia No.12(3): Medicinal and poisonous plants 3.