Usually, however, philodendrons germinate on trees. Crosses between two philodendrons in different sections can occur successfully. The leaves of seedling philodendrons are usually heart-shaped. The resin is also found on the stems, leaves, and roots of philodendrons. As to the toxicity of philodendrons in cats, the evidence is conflicting. Yet another use of philodendrons is for catching fish. Unlike Philodendrons or Pothos who can propagate from just cuttings, Calathea achieve propagation through division. Some philodendrons are also used for ceremonial purposes. These philodendrons typically send their aerial roots downward. "Philodendron xanadu" is a species within the self-heading Meconostigma group of Philodendrons. It is a common host for Anthuriums and Philodendrons, which appear to be unaffected. Philodendrons have both aerial and subterranean roots. These philodendrons have their roots in the ground early in their lives. He amassed a substantial collection of plants at his home, including more than 500 philodendrons. Hemiepiphytic philodendrons can be classified into two types&colon; primary and secondary hemiepiphytes.