Ricinocarpos graniticus is a species of flowering plant in the family Euphorbiaceae and is endemic to the southwest of Western Australia. It is a monoecious shrub with linear leaves and creamy white flowers, arranged either singly, or with a single female flower surrounded by one or two male flowers.
Ricinocarpos graniticus is a monoecious shrub that typically grows to height of up to, its young branchlets glabrous. The leaves are linear, long and wide on a glabrous petiole long. The upper surface of the leaves is smooth and glabrous and the lower surface is covered with woolly white hairs. The flowers are arranged either as a single male or female flower, or with a single female flower surrounded by one or two male flowers. Male flowers are on a slender pedicel long, the sepals joined at the base and more or less glabrous, the sepal lobes egg-shaped, long, the petals creamy white and lance-shaped or oblong, long and wide. Each male flower has about 35 stamens. Female flowers are on a stout pedicel long. Flowering has been observed from June to September, and the fruit is an elliptic capsule about in diameter.[1]
Ricinocarpos graniticus was first formally described in 2007 by David Halford and Rodney Henderson in the journal Austrobaileya from specimens collected in the Darling Range in 2004.[2] The specific epithet (graniticus) means "living on "granitic soil", referring to the granite rock outcrops where this species is found.[3]
This species grows in low scrub on granite outcrops on the Darling Range, with a disjunct population near Newdegate, in the Avon Wheatbelt, Jarrah Forest, Mallee and Swan Coastal Plain bioregions of south-western Western Australia.[1]