Smooth Rattlebox

Overview

The origin of this species is somewhat unclear. A source says it is from South-East Asia, while the other say it is possibly native to tropical Africa or tropical America. It is so perhaps due to its subsequent pantropical naturalization. Now it is commonly found in India, Sri Lanka and South-East Asia.  

Vernacular Names

Hinghai (Thai), Zhu Shi Dou (Chinese), Gestreifte Klapperhuelse (German), Crotalaire Mucronée (French), Kekecrekan, Orok-orok, Telpok (Sundanese, Javanese, Madurese-Indonesia), Gorung-gorung (Philippines).

Agroecology

This species grows naturally on river banks, edges of lakes, extending into woodland, grassland and waste places from 0-1000 m altitude but it tolerates altitude to 1800 m. It absolutely needs light hence shade inhibits its growth strongly. It can live in a wide range of annual rainfall, from 850 mm/year to over 3000 mm/year. The average annual temperature varies from 16-26 °C.

Morphology

• Roots - long, strong taproot
• Stem – stout, slender longitudinal grooves, ribbed with short appressed hairs.
• Leaves - simple, trifoliolate, about 2.5-10.5 cm long, about 6-20 mm broad, elliptical to obovate, blunt or somewhat pointed, apiculate, glabrous above, thinly appressed puberulous below.
• Flowers - bisexual, zygomorphic, terminal inflorescence, 20-30-flowered, 5-merous; calyx 6-8 mm long, corolla about 1.5 cm long, yellow, often reddish-brown veined.
• Fruits – in the form of pods, about 3-5 cm long, 30-40-seeded, yellowish when mature.
• Seeds - heart-shaped, with narrow end strongly incurved, up to 6 mm long, dark grey-green or brown.

Cultivation

It is cultivated by seed and the seedling will emerge after 21-30 days after sowing. The germination rate of fresh seeds is higher compared to the stored ones. The 30 cm tall-plants must be topped in order to promote branching.

Chemical Constituents

Crotolidene, hydroxydihydrobovolide, octacosane, trans-phytyl palmitate, linoleic acid, methyl oleate, ethyl palmitate, and palmitic acid.

Traditional Medicinal Uses

This plant is used for the treatment of urinary problems in traditional medicine. A poultice made of pounded roots is applied to treat painful swelling of joints. While the leaves are extracted and taken as anthelminthic medicine. People in Laos use this plant to reduce fever.