Petalonyx thurberi is a species of flowering plant in the family Loasaceae known by the common names Thurber's sandpaper plant[1] and common sandpaper plant.[2] It is native to the deserts of the southwestern United States and northwestern Mexico, where it grows in sandy and scrubby habitat. It is a rounded or spreading, clumpy subshrub made up of many rough-haired stems approaching one meter in maximum height. The stems are lined with clasping leaves varying in shape from lance-shaped to triangular to oval and sometimes toothed. The inflorescence at the end of the stem is a small, crowded raceme of several flowers. The white flower appears tubular, its petals fused near the spreading tips but open lower, the stamens emerging from outside the corolla.[3]
There are two subspecies, with the rarer, ssp. gilmanii (Death Valley sandpaper plant), limited to the deserts in and around Death Valley.[4]