Traditionally, clonal reproduction has been viewed as an alternative to sexual reproduction and adaptive explanations have sought to compare both modes of 'reproduction'. General theoretical discussions have included a very narrow range of the variation in forms of clonal reproduction and have tended to exclude many of the more common forms found amongst aquatic angiosperms. More recent attempts to explain the adaptive significance of cloning in plants have focused on the dichotomy of compact versus diffusely spreading types and are still too narrow to provide a broad understanding. In this paper the case for the existence of six major categories of selective forces operating on clonal propagules is presented: numerical increase, dispersal, resource acquisition, storage, protection, and anchorage. It is shown that different methods of clonal reproduction differ in terms of these six characteristics. Further, there exists a partial correlation between the syndrome of functional attributes and the habitat relations for a given method of clonal reproduction. In order to develop a more predictive relationship between plant form and habitat affinities it will be necessary to consider the entire growth form and life history. In doing this it will be necessary to recognize the numerous functions performed during clonal reproduction.
