Abstract
Epiphytes are often characterized by small size, specifically adapted to a relatively dry and nutrient-poor habitat. However, this epiphyte syndrome is derived from studies on species-rich and habitat-dominating groups such as orchids and bromeliads. To better understand general trait syndromes of epiphytes, it is important to analyze plant groups that are more transitional in the evolution of epiphytism e.g., the Australasian vireyas (Rhododendron sect. Schistanthe; Ericaceae). Here, we studied the morphology, ecophysiology, and anatomy of 44 species of Rhododendron section Schistanthe from living collections and obtained data for 288 species related to their "life form" (holoepiphytes [= obligatory epiphytes], facultative epiphytes and terrestrial congeners) from the literature. For phylogeny and time-calibrated tree, we used the nuclear ITS (Internal Transcribed Spacers) region. Using different statistics and phylogenetic comparative methods, our results support the hypothesis that holoepiphytic vireyas are smaller in size than the terrestrial ones. Terrestrial vireyas are found at higher minimum and maximum elevation than either facultative or holoepiphytic congeners. We demonstrate that the diversification of tropical Rhododendron is not related to the evolution of the epiphytic life form. Regarding the evolution of traits that are important for water economy, holoepiphytic vireyas do not differ much from their terrestrial relatives indicating that evolutionary steps for specialization towards an holoepiphytic habit are in their initial stages in Rhododendron. Given the large species diversity of the group conclusions based on the subset used here must be considered preliminary. However, our results provide the basis for more detailed future studies.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Perspectives in Plant Ecology, Evolution and Systematics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.