Distinguished by five petals taking shape as banner, wings, and keel – one petal with two lobes form the banner, two petals side by side form the wings, and two fused petals form the keel below. They also form distinctive pea pods and usually have pinnate leaves, meaning a single leaf with many leaflets. They are often climbing plants with grasping tendrils and as legumes, important in the nitrogen cycle, converting nitrogen in their underground nodes with help from nitrogen-fixing bacteria into a form of nitrogen plants can use.
