The velamen protects photosynthetic orchid roots against UV-B damage, and a large dated phylogeny implies multiple gains and losses of this function during the Cenozoic.

Findings indicate an additional role for the epiphytic orchid velamen previously thought to function solely in absorbing water and nutrients, which arose following an ancient duplication of CHS, and has probably contributed to the family's expansion into the canopy during the Cenozoic.