originates in Europe and Asia but is now found growing in about half the states in the US, mostly in the west and south. The plant is similar to the more widespread melilotus officinalis
, the main difference being the shorter yellow corolla (1/8 of an inch cf. 1/4 of an inch). Leaves are odd-pinnate, divided into 3 leaflets which have sharp teeth along the edges are are narrow at the base, blunt or flat at the tip (melilotus officinalis has pointed leaflets). Leaflets tend to fold up along the axis and are often orientated upwards, at right angles to the stalk.
The inflorescence is a narrow vertical cluster, a little less than an inch in diameter, containing several dozen flowers. Each flower has a green calyx formed of five, partly fused lobes, while the corolla opens to five yellow petals, with the familiar pea structure. The upper banner petal is curved back by about 45 degrees.