Lotus junceus is a species of legume known by the common name rush deervetch. It is endemic to California, where it is known from the northern and central coast and the coastal mountain ranges. It can be found from beaches inland to serpentine slopes and chaparral. It is a hairy, prostrate or spreading perennial herb lined with leaves each made up of small oval leaflets. The flower cluster bears up 8 yellow pea-like flowers each up to about a centimeter long. The fruit is a small beaked legume. The fruit beak curves a lot, the keel can exceed the wings, the calyces are entirely red sometimes, and the stems can be darker.