Acradenia is a small genus of two species of evergreen trees or shrubs in the family Rutaceae (order Sapindales), endemic to Australia. Plants are unarmed with simple hairs and bear trifoliate, palmately compound leaves arranged in opposite pairs, lacking domatia; leaflet margins are entire or crenate. The flowers are bisexual, carried in axillary or terminal panicles. Each flower typically has five sepals (1–1.5 mm long, basally fused and persistent in fruit), five free imbricate petals, and usually ten free stamens of alternating lengths that spread outward. The gynoecium consists of usually five basally fused carpels, each bearing a distinctive prominent abaxial gland, with two ovules per locule. The fruit is a cluster of one to five basally fused, transversely ridged follicles (cocci) with truncate tips; each follicle dehisces to release a single smooth, shiny brown seed approximately 5 mm in length. The genus was first formally described in 1853 by Richard Kippist in the Proceedings of the Linnean Society of London, with A. frankliniae designated as the type species. Its two species are Acradenia euodiiformis (yellow satinheart or bonewood), distributed in New South Wales and Queensland, and Acradenia frankliniae (whitey wood or wirewood), restricted to Tasmania. The closest known relative of Acradenia is Crossosperma, a genus from New Caledonia.
Distribution
Acradenia is endemic to Australia. The two species have disjunct ranges: Acradenia euodiiformis occurs in New South Wales and Queensland, while Acradenia frankliniae is restricted to Tasmania.
Taxonomy Notes
The genus Acradenia was first formally described in 1853 by Richard Kippist in the Proceedings of the Linnean Society of London, with A. frankliniae as the type species. Its closest relative is Crossosperma, a genus native to New Caledonia. The carpels bear a distinctive prominent abaxial gland, a feature noted in Flora of New South Wales.
