Thryptomene costata is a species of flowering plant in the family Myrtaceae and is endemic to Western Australia. It is an erect shrub with upward pointing, egg-shaped leaves with the narrower end towards the base, and white or pink flowers with five petals and ten stamens.
Thryptomene costata is an erect shrub that typically grows to a height of and has many branches from just above ground level. Its leaves are pointed upwards and egg-shaped with the narrower end towards the base, long and wide on a petiole long. The flowers are arranged in pairs in up to four adjacent leaf axils, on peduncles long with egg-shaped bracteoles long that fall from the flower buds. The flowers are in diameter with egg-shaped, white or pale pink sepals long. The petals are white to deep pink, long and there are ten stamens opposite the sepals and petals. Flowering occurs from May to November.[1]
Thryptomene costata was first formally described in 2001 by Barbara Lynette Rye and Malcolm Eric Trudgen in the journal Nuytsia from specimens collected by Trudgen in 1978.[2] The specific epithet (costata) means "ribbed", referring to the floral cup.
This thryptomene grows on granite outcrops and other rocky places between Cue and Wubin and from Tallering Peak to near Menzies in the Avon Wheatbelt, Coolgardie, Murchison and Yalgoo biogeographic regions.
Thryptomene costata is classified as "not threatened" by the Western Australian Government Department of Parks and Wildlife.