Platysace is a genus of approximately 22 species of woody perennial herbs, shrubs, and subshrubs belonging to the carrot family Apiaceae. The genus is entirely endemic to Australia, with species distributed across Western Australia, New South Wales, Queensland, Victoria, and the Northern Territory.
Plants in the genus bear simple or lobed leaves and produce flowers at the ends of branches arranged in compound umbels — the characteristic branched, flat-topped flowerheads typical of Apiaceae. The small flowers are bisexual or male, occasionally lacking sepals, and bear white, cream-coloured, or pinkish petals that are elliptical to egg-shaped. The fruit consists of two compressed mericarps.
Platysace was first formally described in 1845 by the German botanist Alexander von Bunge in Johann Georg Christian Lehmann's work Plantae Preissianae. The type species is Platysace cirrosa. Taxonomically, the genus occupies an unusual position within Apiaceae: a 2021 molecular phylogenetic study found it to be sister to the rest of the entire family, meaning it does not fit within any of the four established subfamilies, and some authors have proposed placing it in a subfamily of its own.
Around 22–23 species are currently accepted by the Australian Plant Census. Notable members include Platysace lanceolata (shrubby platysace), widespread in southern Australia, and Platysace linearifolia, found in eastern states.
Distribution
Platysace is endemic to Australia, with species occurring primarily in Western Australia and also recorded from New South Wales, Queensland, Victoria, and the Northern Territory.
Taxonomy Notes
Platysace was first described in 1845 by Alexander von Bunge in Lehmann's Plantae Preissianae, with Platysace cirrosa as the type species. A 2021 molecular phylogenetic study found the genus to be sister to the rest of Apiaceae — outside all four of the family's established subfamilies — and it has been proposed that Platysace could be recognised in a subfamily of its own.
