Allamanda cathartica L.
Common Name: Allamanda, Golden-trumpet, Common Allamanda, Yellow Allamanda, Akar Cempaka Hutan, Bunga Akar Kuning, Akar Chempaka Kuning, Allamanda Trumpet Vine, Golden Trumpet Vine
Allamanda cathartica, commonly called as Allamanda, is a genus of tropical, tender, perennial evergreen. There are 15 species, commonly grown in gardens throughout the tropics, where some species have become naturalised and even invasive. In temperate countries such as the United States, they are grown as greenhouse plants or houseplants for their freely produced, brightly coloured, golden yellow flowers that contrast with the shiny dark green leaves. The simple leaves are arranged in groups of three or four along the branches (i.e. the leaves are whorled or verticillate). They are borne on very short stalks (i.e. petioles) only 2-5 mm long and have blades that are egg-shaped in outline (i.e. obovate) to somewhat elongated in shape (i.e. oblong-lanceolate). These leaves (5-17 cm long and 2.5-6 cm wide) have a narrowed (i.e. attenuate) base, entire margins, and a pointed tip (i.e. acuminate apex). They are somewhat shiny in appearance, relatively thick and leathery in nature, and hairless (i.e. glabrous).
The large flowers (7-11 cm long and 5-7.5 cm wide) have five bright yellow petals that are fused together at the base to form a tube (i.e. corolla tube) about 4-8 cm long. This tube has reddish markings on the inside and is topped with five spreading petal lobes. The flowers also have five sepals (8-22 mm long) that are fused into a much smaller, greenish-coloured, tube at their bases (i.e. a calyx tube). Each flower also has five stamens that are joined directly onto the inside of the petals (i.e. adnate to the corolla tube) and a long style with two small branches at its tip. The flowers are borne in loose clusters (i.e. cymes) near the tips of the stems, each containing about ten flowers. Individual flowers are borne on short stalks (i.e. pedicels) about 5-7 mm long and the petals (i.e. corolla lobes) are folded and twisted when in bud. Flowering probably occurs mostly during spring and summer. Allamanda forms a sprawling shrub or woody climber that tends to sprawl and twine itself around a support and will need to be tied to a trellis or other support. If grown outdoors in the landscape, the plants should be cut back and overwintered as indoor container plants before the first freeze. Note that, once indoors, the plant requires a site with bright light. Whether indoors or out, the plant does require ample moisture and good drainage.
Reference
1. https://plants.ces.ncsu.edu/plants/allamanda-cathartica/
2. https://www.nparks.gov.sg/florafaunaweb/flora/1/3/1303
3. https://keyserver.lucidcentral.org/weeds/data/media/Html/allamanda_cathartica.htm