Micromelum

Description

Micromelum is a genus of flowering plants in the citrus family, Rutaceae. There are several subfamilies in the citrus family, with genus Citrus classified in the Aurantioideae. Micromelum belongs to the other tribe in this subfamily, Clauseneae. It is the only genus of the subtribe Micromelinae, which are known technically as the very remote citroid fruit trees. Micromelum includes about 9 or 10 species of plants distributed in Asia, Australia, and the Pacific Islands. The genus includes evergreen and deciduous shrubs and trees. The leaves are glandular and aromatic, containing essential oils. They are alternately arranged. They are usually pinnate, divided into up to 23 leaflets, except for M. diversifolium, which sometimes has undivided leaf blades. The leaflet edges are smooth or toothed. There are sometimes glandular stipules. The inflorescence is a large panicle, sometimes flat-topped like a corymb, growing from the leaf axils or at the ends of branches. The flowers have five narrow petals in shades of green, white, or yellow, borne in a hairy, cup-like calyx with five lobes or five separate sepals. The odor of the flowers has been described as "malodorous" and "foetid". There are 10 stamens and 1 to 5 styles. The genus is noted for the unusual curving or twisting of the chambers in the ovary. The fruit is a berry up to a centimeter long. It is yellow, orange, or red, and sometimes fleshy, but it lacks the pulp present in some related fruits, notably citrus. The peel is gland-dotted. Each fruit has 1 to 3 seeds. The plants vary in form, with M. hirsutum being a low shrub sometimes less than a meter tall and M. integerrimum being a tree which can exceed 9 meters in height.