Acronychia chooreechillum, commonly known as mountain aspen, is a species of flowering plant in the citrus family, Rutaceae. This tree is a distinctive component of its native Australian flora, contributing to the biodiversity of the regions it inhabits. The mountain aspen is a medium-sized tree, typically reaching heights of 8 to 20 meters, though it can occasionally grow taller under optimal conditions. Its growth habit is generally upright, forming a dense canopy. The leaves are compound, arranged oppositely along the stem, and are typically trifoliate, meaning each leaf is divided into three leaflets. The leaflets are ovate to elliptic in shape, with smooth or slightly toothed margins, and possess a glossy, dark green upper surface. A notable characteristic of the leaves is their aromatic quality when crushed, a common trait within the Rutaceae family. The bark of Acronychia chooreechillum is usually smooth and greyish, becoming slightly rougher with age. Flowering occurs during the warmer months, producing clusters of small, star-shaped flowers. These flowers are typically white or cream-colored and possess a pleasant fragrance, attracting pollinators. Following successful pollination, the plant develops fruits, which are small, globular drupes. The fruit is initially green and ripens to a yellowish or orange hue. The flesh of the fruit is fleshy and contains seeds. Acronychia chooreechillum is native to eastern Australia, found in Queensland and New South Wales. It thrives in rainforest environments, particularly in wet sclerophyll forests and along rainforest margins, often at higher elevations. It prefers well-drained soils and a position that offers some protection from harsh winds, though it can tolerate a range of light conditions from full sun to partial shade. While primarily a wild species, its attractive foliage and flowers make it a potential candidate for ornamental planting in suitable climates. Ecologically, Acronychia chooreechillum plays a role in supporting local fauna, with its fruits likely providing a food source for birds and other wildlife. Its presence contributes to the structural complexity of the forest ecosystem. While there is no widespread documented use of this species for agricultural, medicinal, or culinary purposes, its native status and botanical characteristics are of interest to botanists and conservationists. The aromatic leaves are a characteristic feature that aligns with other members of the Rutaceae family, which includes many economically important aromatic and citrus species.