Arenaria aculeata (syn. Eremogone aculeata) is a species of flowering plant in the pink family known by the common name prickly sandwort. It is native to the western United States, where it grows mainly in mountainous areas, on rocky slopes and volcanic soils.
This is a mat-forming perennial herb growing in clumps of waxy foliage on short, hairy, glandular stems. The leaves are very thin and pointed, somewhat needlelike, and up to 3 or 4 centimeters long. The inflorescence is an open array of flowers with five lance-shaped to oval white petals each one half to one centimeter long. The fruit is a toothed capsule containing several small yellowish seeds.