Eucalyptus percostata, commonly known as the rib-capped mallee or Devils peak mallee,[1] is a species of mallee that is endemic to South Australia. It has smooth bark, lance-shaped adult leaves, flower buds in groups of seven, creamy white flowers and cup-shaped to conical fruit. It is only known from a few locations in the Flinders Ranges.
Eucalyptus percostata is a mallee that typically grows to a height of and forms a lignotuber. It has smooth whitish bark that is coppery when new. Young plants and coppice regrowth have broadly lance-shaped to broadly egg-shaped leaves that are long and wide. Adult leaves are the same shade of green on both sides, lance-shaped, long and wide tapering to a petiole long. The flower buds are arranged in leaf axils on a peduncle long, the individual buds sessile or on pedicels up to long. Mature buds are pear-shaped, long and wide with a conspicuously ribbed, rounded to conical operculum. Flowering from May to September and the flowers are creamy white. The fruit is a woody, cup-shaped to conical capsule long and wide with the valves near rim level.[2] [3] [4]
Eucalyptus percostata was first formally described in 1990 by Ian Brooker and Peter Lang in Journal of the Adelaide Botanic Gardens from material collected on a track east of Devils Peak, near Quorn in 1986.[5] The specific epithet (percostata) is from Latin meaning "conspicuously ribbed", referring to the operculum.
Rib-capped mallee grows in woodland and mallee in the southern Flinders Ranges between Quorn and Napperby.