How are peanut pods different from most legume pods?

Most legume pods, such as those of peas or beans, are characterized by their ability to split open (dehisce) along one or both edges at maturity to release their seeds.12

In contrast, the peanut (Arachis hypogaea) is distinct due to a phenomenon known as geocarpy. While the peanut flower is produced aboveground, it moves close to the soil surface as it ages. A stalklike structure called a peg then grows from the base of the flower, carrying the fertilized ovules downward into the soil. The pod develops entirely underground, where it matures as a subterranean fruit. These pods typically have a thin, netted, and spongy shell and are contracted between the seeds.312