Data from: 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 to
science. Two new species are described here: Claytonia panamintensis,
known in California only from the Panamint Mountains but ranging
morewidely across southern Nevada, and Claytonia serpenticola. The latter
species shares a similar geographic rangewith C. obovata in the
Klamath-Siskiyou region of northern California and southwestern Oregon,
and these two occur in close sympatry through much of their respective
distributions. We also provide molecular evidence to support retention of
the name C. lanceolata for populations in California that do not fall into
any of the aforementioned new species or combinations. Taxa accepted in
this paper are best distinguished from each other by their habitat (many
are apparently edaphic endemics), betalain pigmentation, inflorescence
architecture, and morphology of cauline leaves, subterranean stems, and
flowers.