This pod has done its job, encasing within its sturdy walls the growing seeds of the next generation of legumes, in this case one of the vetch family. Once the seeds were mature, the pod began to dry out, in the process turning from a lush green to rich brown. And then, when the time was right, the temperature and humidity at optimum levels, the pod split open, flinging its seeds as far and wide as possible to try to ensure the success of the next plant generation.