Chondrus crispus is a small purplish-red seaweed (up to 22 cm long) found on rocky shores and in pools. The fronds grow dichotomously from a narrow, unbranched stipe and are flat and wide with rounded tips. This seaweed is highly variable in appearance depending on the level of wave exposure of the shore and has a tendency to turn green in strong sunlight. Underwater, the tips of the frond can be iridescent.Also known as Irish moss. Together with Mastocarpus stellatus, Chondrus crispus is harvested commercially as carrageen to be used in the pharmaceutical and food industries. May be confused with Mastocarpus stellatus, although the latter species has a rounded stipe, channeled fronds and papillate reproductive bodies.