Extreme phenotypic variation and fitness in lichens

Phenotypic variability is a successful strategy in lichens for colonizing different habitats. Pérez-Ortega et al. study the extreme phenotypic modifications shown by vagrant populations of the cosmopolitan shrubby terricolous lichen species Cetraria aculeata in steppe habits of Central Spain. They observe clear ultrastructural differences between vagrant and typical morphs, which may be related to the presence of intercalary growth in the former, and find genetic differences between vagrant and attached sub-populations. The anatomical and morphological changes lead to greater duration of ecophysiological activity in vagrant specimens. These results, together with a higher biomass of the vagrant morphs found in the localities studied, indicate possible fitness effects and adaptation to dry environmental conditions in steppe habitats.