Common mullein has long been part of a very large family. The figwort family included penstemons, snapdragons, toad flax, and a great many others. The chromosome crunchers have now made off with most of the relatives. Many of them were placed with an unsuspecting plantain family. As a social worker, I would probably have wanted to do a more thorough family study before making this placement. Snapdragons don't seem like a good fit for those weedy lawn plantains.
Mullein has been used medicinally since the ancients, for everything from sore throats to evil curses. Dioscorides recommended it for throat ailments, and that remains its most frequent use. The fuzzy dead stems were used as torches.