Melicope simplex, commonly known as Poataniwha, is a species of flowering plant in the citrus family, Rutaceae, native to New Zealand. This adaptable shrub or small tree plays a role in its native ecosystems and is recognized for its distinct botanical features. Poataniwha typically grows as a dense, erect shrub or a small tree, reaching heights of up to 6 meters, though it can occasionally grow taller. Its growth habit is characterized by a branching structure that can become quite bushy. The leaves are arranged oppositely along the stems and are trifoliate, meaning each leaf is composed of three leaflets. These leaflets are ovate to elliptic in shape, measuring approximately 3-8 cm in length, with margins that are usually entire or finely toothed. The upper surface of the leaves is typically glossy and dark green, while the underside is paler. The bark is smooth and greyish. Flowering occurs from late spring through summer, with small, inconspicuous flowers borne in axillary clusters. The flowers are typically white or pale greenish-white and possess four petals. Following pollination, the plant produces small, four-lobed capsules that mature into fruits. These capsules are typically 4-5 mm in diameter and split open to release small, dark seeds. The native distribution of Melicope simplex is widespread throughout the North Island of New Zealand, extending to some offshore islands. It is found in a variety of habitats, often colonizing disturbed areas, forest margins, scrubland, and coastal environments. It thrives in well-drained soils and can tolerate a range of light conditions, from full sun to partial shade. While it is a native species, it is also cultivated in gardens for its foliage and form, particularly in regions with similar climates. Ecologically, Poataniwha contributes to the understory vegetation of its native forests and scrublands. Its flowers provide a nectar source for native insects, and its seeds are consumed by some bird species. While not widely recognized for significant economic or medicinal uses, its presence is valued within its natural ecological context. Interesting adaptations of Melicope simplex include its ability to colonize a variety of soil types and its resilience in disturbed environments, which allows it to establish and contribute to ecological succession. The trifoliate leaf structure is a notable characteristic that aids in its identification.