Wikipedia
Hesperelaea is a plant genus with only one species, probably now extinct. Hesperelaea palmeri was found only on Guadalupe Island, a small island in the Pacific Ocean, part of the Mexican state of Baja California, about 400 km southwest of Ensenada. The last collection of the plant on the island was in 1875, so the species and the genus must now be presumed extinct. An intensive search for the plant in 2000 was unsuccessful.
At the time of the collection of the type material in 1875, Hesperelaea palmeri was found only in a single canyon on the east side of the island. It was a shrub with broadly lanceolate leaves up to 5 cm long. Flowers were pale yellow, the petals over 10 mm long. The species was unusual in the family in having fully distinct petals.