BAY MIWOK EVENING PRIMROSE: A NEW SUBSPECIES OF OENOTHERA DELTOIDES (ONAGRACEAE) ENDEMIC TO CALIFORNIA

California contains exceptional biodiversity in geography and plant life, including numerous endemic species, some of which are cryptic. The Oenothera deltoides Torr. & Frém. species complex represents a prime example of cryptic diversity. Here, we recognize a new subspecies of Oenothera deltoides, O. deltoides subsp. julpunensis S.F.Jones, subsp. nov., that is a local endemic of windblown sand deposits on the eastern Antioch Dunes sand sheet in the San Francisco Bay-Delta region of California, USA. With the goal of providing clarity to managers of listed species and better understanding of California's diverse flora, we addressed the puzzle of O. deltoides in the region by combining range-wide field surveys with modern genomic tools. We describe the proposed subspecies, its ecology and distribution, and discuss its conservation. As a somewhat cryptic local endemic with small population size and disappearing habitat, the proposed subspecies would benefit from conservation and management to persist as a member of the California flora.