The Flora of Greater San Quintín, Baja California, Mexico (2005–2010)

The plants of San Quintı́n (Baja California, Mexico) were documented through intensive fieldwork and collection of herbarium specimens to create a checklist of species. The region is located near the southernmost extent of the California Floristic Province, and the flora is influenced by the adjacent desert to the south. A total of 435 plant taxa were documented, of which 82% are native plants. Almost one in three native plant taxa in Greater San Quintı́n is a sensitive species, here documented as rare and/or locally endemic, and many taxa have yet to be evaluated fully for rarity and threats. Four major habitats were identified, and a checklist is presented for each. Shell middens and vernal pools represent micro-habitats with unique species that also warrant conservation consideration. All habitats in Greater San Quintı́n are threatened by human activity, and agricultural water use practices are unsustainable. There is a pressing need for conservation of the natural areas that remain in this unique but heavily impacted region. The El Socorro Dunes and the volcanic bay are of particular conservation value with several narrowly endemic taxa. As a transitional area in a global biodiversity hotspot, Greater San Quintı́n is home to many species on the edge of their ranges and may be of critical importance to biodiversity conservation in a changing climate.