Rutaceae is known as an aromatic plant family because of the scent of its volatile oils found in the superficial pellucid gland dots (Brummit, 2007). It is a large family comprising 160 genera and 1650 species. In Peninsular Malaysia, 17 genera occur, including the genus Micromelum.
Two species, Micromelum hirsutum Oliv. and M. minutum Wight & Arn., are found in Peninsular Malaysia. They are shrubs to small-sized trees without thorny branches. The genus is characterised by pinnate leaves, with 7 to 15 leaflets on each side of the midrib, with asymmetric bases. The flowers are white to greenish and have a toothed calyx. The berries turn yellow-orange when ripe and attract birds that disperse the seeds. For example, in Papua New Guinea and Indonesia, M. minutum is known to be one of the food sources of the Red-sided Electus Parrots (Marshall & Ward, 2004).
Apart from Malaysia, M. hirsutum is also found in Indo-China, Thailand and the Andaman Islands. In Peninsular Malaysia, it is commonly found in Kedah, Perak, Selangor and Pahang. The most significant distinctive character is its inflorescence stalks that are covered with dense woolly, matted grey hairs. In contrast, the inflorescence stalks of M. minutum are covered with short soft hairs.
Micromelum minutum has many common names such as lime berry, cluster berry and cemumar in Malay. It occurs in Sri Lanka, the Nicobar and Andaman Islands, Myanmar, Thailand, Indo-China, Malaysia, Indonesia, the Philippines, and south to Australia. It is widely distributed in Peninsular Malaysia, Sabah and Sarawak, where it grows in primary and secondary forest, on hills, forest margins and in disturbed areas. It is also quite common on sandy coasts and in limestone areas that are open and exposed to full sunlight.
Old records state that M. hirsutum was used to prevent disturbance by bad spirits but it is unknown whether it worked or not (Burkill, 1966). The leaves of M. minutum contain coumarins, compounds used in fabric softeners and perfumes (Rahmani et al., 1994). The coumarin content depends on the location and environment where the tree is growing. For example, the coumarin content of the leaves of plants placed under direct natural UV is higher compared to plants kept in the dark (Zobel & Brown, 1995). Old references show that the roots of M. minutum were used to treat malaria or other illnesses involving fever and shivering while the ash from burnt M. hirsutum was used for bathing to reduce a fever (Burkill, 1966). In Southeast Asia, the leaves and roots of both species are used externally to cure skin diseases, for example, ringworm (Jones, 1995).
Neither species is endangered as both are quite common with a wide distribution.
