Boronia megastigma is a species of shrub in the citrus family known by the common name brown boronia. This is one of several species of Boronia cultivated for its intense, attractive scent. It is the main Boronia source of essential oils, while its relative Boronia heterophylla is more often harvested for use as an aromatic cut ornamental. B. megastigma is a small shrub approaching a meter in maximum height. The narrow, thick, linear leaves are arranged in whorls about the thin stem branches. They are dark green and glandular, and are scented, but it is the flower of the plant which is coveted for its oils. All of the organs of the flower contain oil glands and their activity is greatest while the stigma is receptive to pollen, which suggests that production of scent may serve to attract pollinators such as insects. In the wild plant, each flower is about a centimeter wide and shaped like a cup which is brown or dark reddish-purple externally and bright yellow inside. There are several cultivated varieties which bear flowers of different colors. The two main aroma compounds of the oil of this species are β-ionone and dodecyl acetate.