adder's-tongue; a genus of the order of filices, belonging to the cryptogamia class of plants. There are seven species; of which the only remarkable one is the vulgatum, or common adder's-tongue, which is a native of several places of Britain, growing in meadows and moist pastures. The country-people make an ointment of the fresh leaves, and use it as a vulnerary to green wounds; which is a very ancient application, recommended by Matthiolus, Tragus, and others.