Iridescence: a useful criterion to sort gametophytes from sporophytes in the red algaChondrus crispus

Carrageenan analyses ofChondrus crispus Stackhouse from Brittany, France, showed that the iridescent fronds always were kappa-carrageenan dominant and that the non-iridescent ones were lambda-carrageenan dominant, whatever their sizes and their vegetative or reproductive stages. Evidence is presented that the blue iridescence is independent of both the morphology of the fronds and their ecological situation (shelter, exposure). It is suggested that iridescence might be used to sort rapidly the kappa-carrageenan containingChondrus crispus (gametophytes) from the lambda-carrageenan containing ones (tetrasporophytes).