Toivonen, J. M., Horna, V., Kessler, M., Ruokolainen, K., & Hertel, D. (2014).
Interspecific variation in functional traits in relation to species climatic niche optima in Andean Polylepis (Rosaceae) tree
species: Evidence for climatic adaptations. Functional Plant Biology, 41(3),
301-312. doi:10.1071/FP13210.