Cneoridium dumosum, a monotypic species, is mostly restricted to the beaches and hills around San Diego in far south California, the range extending north towards Los Angeles. Plants are densely-branched shrubs, with linear, evergreen leaves, hairless, unlobed and untoothed, dotted with light-colored glands, which contribute to the citrusy aroma.
Flowers consist of four small, yellowish-green sepals, joined only at the base, four larger obovate white petals, a ring of eight stamens and a central ovary topped by a reddish stigma. Stamens are of two different lengths, the longer ones positioned above the sepals. The white filaments are tapering, widest at the base. Anthers are pale yellow-brown. Fruits are spherical drupes, a quarter of an inch in diameter, initially green, ageing to red.