Hypericum japonicum Thunb. ex Murray - HYPERICACEAE - Dicotyledon

Common name : Japanese- or matted- St. Johnswort.

Botany Biology Phenology Ecology Distribution Agricultural importance Cultural control Chemical control

Botany :

Description :

Terrestrial, annual, tufted herb, up to 40 cm tall. Roots fibrous, white or brown. Stem erect or procumbent, quadrangular, solid, glabrous. Stipules absent. Leaves simple, not lobed or divided, opposite, sessile, ovate, less than 2 cm long/wide, glabrous on both sides, dots present, margin entire, apex obtuse, base cordate, parallel-veined. Flowers bisexual, grouped in a terminal one to few-flowered cyme, stalked, petals 5, yellow. Fruits a capsule, opening with 3 valves.

Biology :

Reproduction by seeds; hydro-and ornithochorous.

Phenology :

Flowering November to February; fruiting December to March.

Ecology :

Wet or marshy sites; ditches, stream banks to dry places, roadsides and road banks, terrace banks, sunny places; 0-3400 m alt.; sometime abundant. Upland rice fields.

Distribution :

Indian continent, S.E.China, Korea, Japan, S.E.Asia and Malesia, Australia, New Zealand, Hawaii.

Agricultural importance :

A weed of minor importance, as the plants are very weak and have superficial roots.

Cultural control :

Easily controlled by hand or hoe and by cultivation.

Chemical control :

Post-emergence application of 2,4-D at 500 g/ha or Almix 4 g/ha.

Uses :
Generally, Hypericum japonicum is thought to have astringent and alterative action, and it is used externally to treat swellings, abscesses, scrofula and fungal skin diseases.
In Malaysia, it is applied externally to treat wounds.
In Papua New Guinea, crushed plants are reported to be used internally against malaria, together with ginger and ash salt.
In Viet Nam, is used internally as stomachic and externally as vulnerary on wounds, leech and snake bites, and treat cares and bad breath.
In China medicine, it is applied as vulnary on wounds and leech bites, and to treat bacterial diseases, hepatitis and tumours.

References :
-Lavit Kham. 2004. Medicinal plants of Cambodia.
-Soerjani M., Kostermans A. J. G. H., Tjitrosoepomo G. 1987. Weeds of rice in Indonesia. Balai Pustaka. Jakarta.
-Tavatchai Radanachaless, J.F.Maxwell. 1994. Weeds of soybean fields in Thailand. Multiple Cropping, Center Publications. Thailand.

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