Pimelea williamsonii, commonly known as Williamson's rice-flower,[1] is a species of flowering plant in the family Thymelaeaceae and is endemic to the southern continental Australia. It is a bushy annual subshrub with more or less elliptic leaves and elongated heads of many hairy, brownish flowers.
Pimelea williamsonii is a bushy annual subshrub that typically grows to a height of and has densely hairy young stems. The leaves are more or less elliptic, long and wide on a short petiole. The flowers are bisexual, arranged on the ends of branches in elongated heads up to long. Each flower is on a hairy pedicel, the flower tube about long, the sepals about long, the flowers brownish and covered with short white and long brown hairs. Flowering occurs in most months with a peak in October and November.[2] [3]
Pimelea williamsonii was first formally described in 1919 by John McConnell Black in the Transactions and Proceedings of the Royal Society of South Australia.[4] [5] The specific epithet (williamsonii) honours Herbert Bennett Williamson who discovered the species near Pinnaroo in 1917.
Williamson's rice-flower grows in sand from the Eyre Peninsula and Billiatt Conservation Park in south-eastern South Australia to Annuello and Hattah-Kulkyne National Park in north-western Victoria.