Explanation

Epiphytic roots are also called hygroscopic roots. Epiphyte bear three types of roots clinging, absorbing and hygroscopic aerial. These roots develop in some orchids, which grow as epiphytes upon the trunks or branches of trees. They hang freely in the air and absorb atmospheric moisture with the help of a special spong like tissue called velamen. Velamen is modification of epidemis, e.g., Vanda, Dendrobium, etc.