Tropical understory communities are highly diverse, and plants in these environments must optimize functional traits to ensure ecological and evolutionary success. Campany et al. survey the ecophysiology of two spore bearing vascular plant groups, Selaginella and ferns, in a lowland Costa Rican tropical forest understory.
Selaginella in shade has higher chlorophyll levels and lower light compensation points compared with open habitats, where foliar nitrogen was lower and stomatal densities higher. Co-occurring ferns optimized ecophysiological function differently in tropical forest floors, likely related to evolutionary constraints of micro- and megaphyll leaf physiology. These findings contribute to global explorations of vascular plant trait patterns.