Dumontia contorta is a red seaweed, which is yellowish to dark red in color. and grows to 250 mm tall (occasionally 600 mm). A young is attached by a holdfast, and has tubular and branches. Older plants have a twisted axes and irregular, tendril-like branches. The plants are winter-spring annuals, which decay in late spring, and regrow in the fall.. This alga is native from Norway and Iceland to Spain and Portugal. We consider records from Arctic Canada (James Bay and Ellesmere Island to be cryptogenic, due to possible confusion with Dumontia alaskana, recently described from the Pacific. However, D. contorta has been genetically identified from South Korea, where D. alaskana was also found. The range of both species in the Arctic and Pacific should be examined. Dumontia contorta was first collected in Casco Bay, Maine in 1913, and now ranges from Labrador to Long Island Sound. It occurs on tocks form the mid-tidal level to 30 m depth. This seaweed is common to abundant on the northeast coast from Labrador to Long Island Sound.