Nasturtium gambelii

About

Nasturtium gambellii is a rare species of flowering plant in the mustard family known by the common names Gambel's yellowcress and Gambel's watercress. It is known from three or four scattered occurrences in California. It is also native to central Mexico and Guatemala. Its total U.S. population was last estimated at fewer than 300 individuals. It was federally listed in California, as an endangered species of the United States in 1993.

Summary from Wikipedia