Lotus pinnatus is a species of legume known by the common names meadow bird's-foot trefoil and bog bird's-foot trefoil. It is native to western North America from California into the Pacific Northwest, its distribution extending into British Columbia in just a few rare occurrences near Nanaimo. It grows in moist to wet habitat, such as bogs and spring meadows. It is a hairless perennial herb lined with leaves each made up of green oval leaflets each 1 to 2.5 centimeters in length. The inflorescence is an array of up to 10 pealike flowers between 1 and 2 centimeters long. Each flower has a bright yellow banner, or upper petal, and white lower petals. The fruit is a slender, elongated legume pod up to 5 centimeters long but just a few millimeters long.