Observations suggest that most Pothos species are root climbers sensu Schimper (1903). However, it is nearly impossible to ascertain whether the plants remain in contact with the ground throughout their life cycle or whether for at least some of the time they lose contact with the ground, i.e. that they are hemiepiphytes (see Putz & Holbrook, 1986; Croat, 1990).
Field observations suggest that the function of the eocaul (see Boyce & Hay 1998) is to locate a climbing host on which to establish juvenile shoots. It is apparent that once this function is satisfied the eocaul soon withers. The question is unanswered whether the eocaul always dies before the juvenile shoot sends down feeder roots and re-establishes contact with the ground or whether there is a period when the plant is separated from the ground. If the latter, then many Pothos species should be classed as secondary hemiepiphytes (see Putz & Holbrook, 1986).
Of species I have observed P. grandis seems habitually to spend at least some of its life free from the ground and thus should be called a secondary hemiepiphyte. However, this observation is based on a very few plants in one area of limestone in which there were few sizeable trees. Habitat data for P. grandis from other localities suggests that degraded woodland on steep limestone is an atypical habitat for the species and thus my observations are based on an atypical set of ecological circumstances.
Part of the problem with life form observations is that it is seldom easy to trace a mass of interlaced adherent stems back to a single source of ground contact and virtually impossible to ascribe the points of ground contact to a particular time in the plant’s development.