Phaseolus filiformis is a wild legume species native to the Southwestern US and Mexico. While the species is common in Arizona and Baja California, only one occurrence has ever been found and collected in California; in a small wash on the eastern slopes of the Santa Rosa Mountains from 1982, far from the Arizona and Baja California borders. San Diego Botanic Garden (SDBG) made an attempt to locate this occurrence in the spring of 2022 with no success. However after a significant summer monsoonal rain season in 2022, SDBG Science and Conservation staff again surveyed the site and were able to successfully locate the plant, 40 years after its first and only previous collection. SDBG continued to survey the occurrence through the spring of 2023 to thoroughly map the occurrence and make seed collections. These seed collections will be added to the SDBG seed bank as well as the NLGRP seed bank in Fort Collins, Colorado.