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Asystasia gangetica (L.) T. Anderson

Asystasia gangetica (L.) T. Anderson

Family

Acanthaceae

Synonyms

Justicia gangetica L., Asysta­sia coromandeliana Nees.

Vernacular Names

Malaysia

Rumput bunga putih, rumput hantu, rumput nyonya.

Philippines

Asistasiya (Tagalog), bulak-bulak (Subanun).

Thailand

Baya, yaya.

Geographical Distributions

Asystasia gange­tica is indigenous in tropical Africa and Asia, but has been distributed pantropically. In Southeast Asia, it is recorded from Malaysia, Thailand, Indonesia and the Philippines.

Description

Asystasia gange­tica is an erect, ascending or clambering herb that can grow up to 0.3-1.25 m and it is with quadrangular pilose stem.

The leaf is ovate to deltoid, measuring 3-7.5 cm x 1.5-5 cm, with obtuse to truncate base, acuminate at apex, hairless to sparingly hairy especially on the veins and with numerous bar-like cystoliths that are visible on the upper surface. The petiole is 1-3 cm long.

The inflorescences are in terminal racemes, measure up to 16 cm long and with flowers directed to one side only. The flowers are on short pedicels, white to yellow, and white with purplish throat or violet. The sepal is 5-lobed. The lobes are lance-shaped and measure 5-7 mm long. The petal is funnel-formed, measures up to 4 cm long and with 5 semiorbicu­lar lobes about 1 cm wide. There are 4 stamens and 2-lobed stigma.

The fruit is an oblongoid capsule and measures up to 13 mm x 2 mm.

There are 2-4 seeds which are ovoid, flat and measuring about 1 mm x 0.75 mm.

Ecology / Cultivation

Asystasia gange­tica is found along roadsides and riverbanks, in semi-waterlogged areas as well as well-drained cultivated areas. In 1976, it became very widespread in oil palm plantations in Penin­sular Malaysia and by 1983, it had infested large tracts of pineapple lands on peat soils in the south­eastern region of Johore. It is a shade-loving plant and optimum photosynthesis occurs between ⅓ to ½ full sunlight. With no weeding, its proportion in the undergrowth of young oil palm plantation increased in a period of 2 years from 25 % to 84 %. It grows, even though slowly, under a closed canopy of oil palm with less than 10% full sunlight. Howev­er, in areas with a dry season of 4 months or more, it may not survive. It thrives on sedentary soils, coastal alluvium, peat soils with 85 % organic mat­ter and pH(H20) 3.5-4.5, sandy loams and clays.

Line Drawing / Photograph

BOT00372

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References

  1. Plant Resources of South-East Asia No.4: Forages.