Prostanthera, commonly known as mintbush or mint bush, is a genus of about 100 species of flowering plants in the mint family Lamiaceae, and all are endemic to Australia. Plants are usually shrubs, rarely trees with leaves in opposite pairs. The flowers are arranged in panicles in the leaf axils or on the ends of branchlets. The sepals are joined at the base with two lobes. The petals are usually blue to purple or white, joined in a tube with two "lips", the lower lip with three lobes and the upper lip with two lobes or notched. Description Plants in the genus Prostanthera are usually shrubs or subshrubs, rarely trees, with leaves arranged in opposite pairs. The flowers are arranged in panicles in leaf axils or on the ends of branchlets with bracts and bracteoles at the base. The sepals are joined at the base but with two lobes. The petals form a tube with two lips, the lower lip with three, usually spreading lobes and the upper lip with two lobes or a notch at the tip. The petal tube is bluish purple to white or more or less red. There are four stamens, the anthers often with a small appendage. The ovary has four lobes and the tip of the stigma has two branches. Taxonomy The genus Prostanthera was first formally described in 1806 by Jacques Labillardière in his book Novae Hollandiae Plantarum Specimen and the first species he described was Prostanthera lasianthos. The word is derived from the Greek for an appendage. Within the flowers are small spur-like appendages on the anthers. Ecology Prostanthera species are used as food plants by the larvae of hepialid moths of the genus Aenetus including A. eximia and A. ligniveren. Uses Mint bushes are cultivated as ornamentals and for essential oils and spices. Species list The following is a list of species accepted at the Australian Plant Census as at August 2020: Prostanthera albiflora B.J.Conn (W.A.) Prostanthera albohirta C.T.White (Qld.) Prostanthera althoferi B.J.Conn (W.A., N.T., S.A.) Prostanthera althoferi B.J.Conn subsp. althoferi (W.A.) Prostanthera althoferi subsp. longifolia B.J.Conn (N.T., S.A.) Prostanthera ammophila B.J.Conn (S.A.) Prostanthera arapilensis M.L.Williams, Drinnan & N.G.Walsh (Vic.) Prostanthera askania B.J.Conn (N.S.W.) – tranquility mint-bush Prostanthera aspalathoides A.Cunn. ex Benth. (S.A., N.S.W., Vic.) – scarlet mint-bush Prostanthera athertoniana B.J.Conn & T.C.Wilson (Qld.) Prostanthera baxteri A.Cunn. ex Benth. (W.A.) Prostanthera behriana Schltdl. (S.A.) Prostanthera caerulea R.Br. (N.S.W.) – lilac mint-bush