Do secondary hemiepiphytes exist?

Abstract

AbstractFor decades, tropical ecologists distinguished primary (PH) and secondary hemiepiphytes (SH) as two structurally dependent life forms with an epiphytic phase at, respectively, the beginning or the end of their ontogeny. However, the use of these terms has been criticized repeatedly because the term “hemiepiphyte” suggests an unsubstantiated biological similarity in ontogeny, and worse, because it is often used without a qualifier, which makes unambiguous interpretation of the life history of such species impossible. In this paper, we go one step further and ask the question whether an ontogenetic trajectory as described by the term “secondary hemiepiphyte” does exist at all. We show that until now all evidence available for the three families that were traditionally listed as taxa with SHs (Araceae, Cyclanthaceae, Marcgraviaceae) falsifies such claims, but critically discuss reports of possible SHs in other families. In all these cases unambiguous conclusions about the existence of any SH are difficult, but our detailed discussion of potential candidates is meant to provide the basis for focused field studies. Irrespective of the outcome of these studies, we urge researchers to abandon the use of the term SH for the time being: Terminological issues can be discussed once there are data.