Cryptantha wigginsii I.M. Johnston (Boraginaceae) had previously been known from a single collection made in April 1931, at a locality 18 miles south of Tijuana, Baja California, Mexico. This species is distinctive and unique in the genus in having nutlets with a surface that is smooth and glossy near the base and densely tuberculate at the apex. Because of the absence of subsequent collections, the species was presumed extinct. However, a population of C. wigginsii was recently discovered in Carlsbad, San Diego Co., California, constituting a new county, state, and country plant species record. Subsequent field investigations and study of (mis-identified) Cryptantha specimens at several California herbaria has turned up additional documented populations of this species in the USA and coastal northwestern Baja California, Mexico. In addition to the three adjacent Carlsbad populations and the type locality in Baja California, populations known to date include: 1) five from Santa Catalina Island, Los Angeles Co.; 2) one from Riverside Co.; and 3) three from northwestern Baja California. Cryptantha wigginsii is commonly found in, but apparently not restricted to, clay soil. Although additional populations may be found now that the taxon has been rediscovered, it is rare enough to warrant future listing as a sensitive and rare plant. Appropriate measures should be taken to preserve existing populations, some of which may be in danger of extirpation. The identification of vouchers of this species from existing herbarium collections highlights the need for depositories of plant collections and for their continued study by taxonomists and systematists.