Abroma augusta (L.) L.f.

Abroma augusta (L.) L.f.

Family

Sterculiaceae

Synonyms

Abroma fastuosum Jacq., Theobroma augusta L., Abro­ma mollis DC.

Vernacular Names

Malaysia Rami sengat.
English Devil's cotton, perennial Indian hemp, abroma.
Indonesia

Kapasan (Javanese), kaworo (Sun­danese), rebong pengayoh (Lampung).

Philippines Anabo (Ibanag, Ilokano, Tinggian, Tagalog, Bisaya), ambong (Tagalog), pakalkal (Pampango).
Thailand Thian dam (Cen­tra), thian dam luang (Chiang Mai).
Vietnam

Chi tai m[ef]o, b[oo]ng v[af]ng.

French

Abrome, abrome royal.

Geographical Distributions

Abroma au­gusta is distributed from India, throughout South­east Asia to southern China, the Solomon Islands and northern Australia. It is sometimes cultivated in India and New Guinea and experimental plant­ings have been set up in the Philippines and Africa (Uganda, Democratic Republic of Congo).

Description

Abroma au­gusta is an erect shrub or small tree that can grow up to 2-4 m tall, normally branching at the height of 1-2 m and is often multi-stemmed from the base. The stem and branches are with tenacious bark, which is smooth or armed with prickles. All parts are with prickly-pointed, irritating, stellate hairs and sometimes with glandular hairs. The orthotropic branches usually remain vegetative while the flowering branches are usually plagiotropic.

The leaves are arranged alternate, simple, highly variable but two main forms exist (hetero­phylly), lobed (often on plagiotropic branches) or unlobed (often on orthotropic branches).

The unlobed form is with petiole up to 1.5 cm long, with lance-shaped blade, measures 16-23 cm x 9-12 cm, heart-shaped at base, denticulate and palmate-pinnately veined while the lobed form is with petiole 10-40 cm long, 3-5-lobed blade, cor­date-ovate in outline, measures up to 30-40 cm x 30-40 cm, with palmately 3-5-7-veined base and irregularly dentate margin.

The inflorescence is a leaf-opposed or terminal and 1-4-flowered cyme (usually only 1 flower devel­ops). The flowers are pendent, 3-5 cm in diametre, bisexu­al and 5-merous. The peduncle and pedicel are each 1-3 cm long and slightly enlarged in fruit. The sepal is deeply di­vided, with 5 entire lobes, triangular, measuring about 15-20 mm x 6 mm and greenish. There are 5 petals which are spoon-shaped, measuring 2-3.5 cm x 1 cm, concave and white at base, with dark purple, red or yellow blade and fringed. The staminal tube is short, with 5 fascicles of anthers that alternat­e with 5 petal-like staminodes apically. Each fascicle is with 3(-4) anthers. The pistil is with a 5-lobed and 5-celled ovary which is 2-3 mm long, that contains numerous ovules, and 5 stigmatic style branches which are 1-2.5 mm long.

The fruit is an obconical capsule, measures about 4-5 cm x 3-4 cm, rounded at base, with truncate top, 5-winged and angled, beaked sometimes, enveloped by a slightly en­larged sepal, densely prickly hairy, with apical portion loculicidal, septicidally dehiscent lateral parts and with numerous seeds. The seed is cylindrical to obovoid, measures 3-4 mm x 2 mm, without wings or aril and black.

Ecology / Cultivation

The distribution area of Abroma augusta is characterised by mean daily temperatures of 27-30°C in the hottest months, an average annual rainfall of at least 1500 mm, and a high relative humidity. It is not suitable for areas with a marked dry season. A. augusta is not frost-hardy and so not found at altitudes above 1100 m. It is a short-day plant. The best soils for A. augusta are fertile alluvials with a good structure and drainage, as it does not tolerate waterlogging for a long period. However, it will also survive and grow when soil conditions are less favourable. When oc­curring naturally, A. augusta is found in thickets or tufts, secondary forests, waste places and village borders and along railways and roads, seemingly preferring forest edges and the banks of clearings or watercourses. As a light-loving plant, it does not occur in primary forest. In the Moluccas, it oc­curs in dry valleys on poor, sandy locations or in fallow fields.

Line Drawing / Photograph

Abroma_augusta_L._L.f._2

References

    1. Plant Resources of South-East Asia No.17: Fibre plants.