The hairs on the tail help the fruit better catch the wind and blow it to new locations. The tail curls when dry and uncurls when moist. This change between curled and uncurled can actually drill the seed into the soil where it may grow to become a new shrub.
It is part of the rose family. The common name "mahogany" comes from the hardness and color of the wood, although the genus is not a true mahogany.