Chondrus crispus, commonly known as Irish moss, is a species of red algae, belonging in the Rhodophyta phylum, that can grow up to 22 cm long and is found on rocky shores along the Atlantic coasts of Europe and North America. This species features fronds that grow dichotomously from a narrow, unbranched stipe, expanding into flat, wide blades with rounded tips. Its color varies from bright green near the surface to deep red at greater depths.