Iridescent Chondrus crispus. Many specimens have much smaller amounts of iridescence. May 2017. North Yorkshire, England.Flashing on and off of the rays on P. pellucida living on the Laminaria fronds as they wave about and change the angle of light incidence, may distract from the animal’s outline, or it may it camouflage by resembling neighbouring iridescent weeds such as Chondrus crispus.