Agonis flexuosa is a species of tree that grows in the south west of Western Australia. It is easily the most common of the Agonis species, and is one of the most recognisable trees of Western Australia, being commonly grown in parks and on road verges in Perth. The species is commonly known as Western Australian peppermint, Swan River peppermint or peppermint, and willow myrtle for its weeping habit. The Noongar peoples know the tree as Wanil, Wonnow, Wonong or Wannang. A. flexuosa occurs mainly as a small and robust tree, usually less than 10 metres tall, although it may grow to 15 metres. It has fibrous brown bark, long narrow dull-green leaves, and tightly clustered inflorescences of small white flowers in the axes. It grows in a weeping habit, and looks remarkably like the weeping willow from a distance. Leaves are narrow and reach a length of 150mm. It is most readily identified by the powerful odour of peppermint emitted when the leaves are crushed or torn. It flowers between August and December. The fruit is a hard capsule, 3 – 4 mm across, with three valves containing many small seeds. The genus name Agonis comes from the Greek agon, 'a cluster', referring to the arrangement of the fruits. The species name flexuosa is Latin for 'full of bends', referring to the zig-zag course of the stem, which changes direction at each leaf node. It was originally placed in the genus Leptospermum by Sprengel in 1819, but Schauer placed it in Agonis in 1844. The two recognised varieties are, Horticultural variants are probably derived from the widespread population, growing as shrubs or trees and perhaps being flowerless. Some commercially produced cultivars include Agonis ‘Belbra Gold’ and Agonis ‘Fairy Foliage’. The cultivar Agonis 'Nana' is a dwarf form that is commonly seen in Perth as a hedge.