Medicago polymorpha is a plant species of the genus Medicago. It is native to the Mediterranean basin but found throughout the world. It forms a symbiotic relationship with the bacterium Sinorhizobium medicae, which is capable of nitrogen fixation. Common names include California burclover, toothed bur clover, toothed medic and burr medic.
Being a member of the Leguminosae family, the flowers are clover-like, lipped and clustered. Flowers, 3-6 mm long, are small, bright yellow, and cluster into flower heads of 2 to 10 flowers at the stem tips.