Greek myths describe Iris, the goddess of the rainbow, as a messenger for
the Olympian deities. The characteristics of the alga Iridaea flaccida
strikingly reflect its namesake. The same properties of light which
produce a rainbow provide Iridaea's surface with its brilliant iridescence.
Vibrant colors wash across the thallus surface due to the multilayered
construction of its cuticle. Flaccida subtly manages to communicate its
phase of life history to the casual observer--yet it lives an isomorphic
existence. Both its iridescent cuticle and the differences in blade strength
between its life phases provide insights into the adaptations of wave-swept algae to
mechanical stress.