Flowers: small; seldom more than two, or three clustered on a peduncle; Corolla: papilionaceous. Pods: one inch in length; inflated, and having numerous seeds. Leaves: short; lanceolate,; almost sessile with arrow-shaped stipules at the base. Stem: erect; much branched and beset with dull bristles.
After the seeds have ripened and become detached, the pods of this plant make very cunning little rattles, as every country child knows; and this fact is referred to in its common and Greek names. Unfortunately, the seeds and leaves contain a poisonous substance which causes animals that eat of them to slowly decline in vigour.
C. rotundifolia is a prostrate species that is well known in parts of the south from Virginia to Mississippi. It favours a dryer soil than the above plant. Its seed pods are very similar.