Epiphytes, plants which grow attached to others without being in any way parasitic upon, or deriving any nourishment from them. They are most numerous in the moisture-laden climate of equatorial forests, having commonly aerial roots, by which they absorb atmospheric moisture. Many ferns, such as the elk's-horn (Platycerium), orchids and Tillandsias live in this way. The ivy (q.v.) and some Tropaeolums approximate to the habit, living for some time after connection with the ground has been severed.