A new white-rayed Layia, L. erubescens B.G.Baldwin, is described from the Central Coast of California. This species, previously not recognized as distinct from L. glandulosa (Hook.) Hook. & Arn., is evolutionarily and ecologically discrete, occurring in loose, fine sand of stabilized backdunes and sandhills from central San Luis Obispo to southern Santa Barbara counties. It differs from L. glandulosa and other members of Layia by the character-state combination of being strongly aromatic (resinous-spicy odor), with a central stem often strictly erect, proximal leaves often deeply lobed, sometimes with minor secondary lobes, ray corollas generally aging pink to rose, and pappus scales narrowly linear-attenuate, 0.8–0.13(0.19) mm wide. Previously published phylogenetic analyses indicated that L. erubescens is an evolutionary outlier to L. glandulosa in its newly restricted sense, which is more closely related to L. discoidea than to L. erubescens. Layia erubescens is declining and of major conservation concern as a result of habitat loss from development of coastal areas and aggressive invasion throughout its range by perennial veldt grass (Ehrharta calycina Sm.).