Decumbent annual, with branches 10-50 mm tall. Leaves petiolate, clustered near base in whorls of 4, ovate to elliptic, dorsiventrally flattened and slightly convex above, 2-4 x 2-3 mm, glabrous. Flowers in loose, mostly terminal clusters, on slender pedicels, ± cup-shaped, petals 1.4-2 mm long, white.
Like C. oblanceolata but lower leaves in clusters of 4.