How does a legume fruit split open when it matures?

Most legume fruits are dehiscent, meaning they are designed to release their seeds by splitting open at maturity.1

This process occurs as the fruit dries out, causing the single carpel of the pistil to dehisce, or split, along one or both of its edges, known as sutures. While this is the standard mechanism for many plants in the Fabaceae family, such as peas and beans, it is important to note that not all legumes open this way. Some species, including peanuts and carobs, are indehiscent and do not naturally split open when ripe.21