The western spring beauties, Claytonia lanceolata (Montiaceae): a review and revised taxonomy for California

The taxonomic history of Claytonia lanceolata is fraught with confusion. Poor preservation of diagnostic characteristics on museum specimens and incomplete original descriptionsmade from limited reference material have resulted in inadequate characterization of morphological features and geographic distributions, particularly for plants in more xeric areas of California. In this paper, we investigate populations previously thought to belong to C. lanceolata and provide an updated taxonomy for Californian taxa based largely on morphological observations and geographic records. These data are corroborated by evidence of genetic polymorphisms and ecological divergence. Claytonia obovata was synonymized with C. lanceolata in 1966 and remained unrecognized until now because previous treatments misinterpreted morphological variation in C. lanceolata s. s. Claytonia peirsonii is a new combination for a species comprising four subspecies endemic to the Desert Southwest, three of which are new t...