The fruits of Astragalus species are often somewhat inflated, but the balloon milkvetch takes that to an extreme with its puffy and very attractive pods. I have seen this plant a few times and it is always a treat. The inflated pods dry to a paper-thin material which is very easily blown around in the wind on the rocky slopes and ridges that the plant likes to grow on, seed spilling out as the pod tumbles away. The fruits of plants are often the most interesting parts of them. So make sure you inspect plants even after their flowers are gone. Seed dispersal strategies are endlessly fascinating to learn about!