Jointvetch seedlings superficially resemble Hemp Sesbania. One of the key differences is that the first true leaf of jointvetch is compound and that of Sesbania is simple. The leaf of jointvetch is pinnate compound, meaning it resembles a feather. The individual leaflets are longer at the base than the tip, giving it a tapered appearance. The flower of jointvetch, like other legumes, has a papillionaceous corolla; it resembles a butterfly. The throat is often reddish as are the veins in the petals. It is on a distinct stalk or peduncle.

The fruit of jointvetch is a segmented pod. The ripe pod breaks at each joint and remains with the seed. The stipules of jointvetch are distinct appendages where the leaf meets the stem. They can be pulled off, which helps to distinguish jointvetch from Sesbania.