The floating roots are swollen spongy and have large aerenchyma. They provide buoyancy to the plant and are also respiratory in function. These are found in Jussiaea, Utricularia. Cuscuta is total stem parasite. The parasite penetrates into the host through sucking or parasitic or haustorial roots and develops a connection between the conducting systems of two plants. Viscum is partial stem parasite. The parasite sends a primary haustorium or suckers into the host and obtaining water and minerals from the host. Vanda is epiphytic herb. It contains adventitious aerial roots. The roots are covered by a hygroscopic velamen tissue which absorbs water from the atmosphere.