Cartilaginous, dark purplish-red, red, yellowish or greenish fronds to 150 mm high, gametophyte plants are often iridescent under water when in good condition. Stipe compressed, narrow, expanding gradually to a flat, repeatedly dichotomously branched frond, in tufts from a discoid holdfast. Axils rounded, apices blunt or subacute, frond thicker in centre than margins. Very variable in breadth of segments. Very variable in branching, colour and thickness.
On rocks, lower intertidal and shallow subtidal, in pools in the mid-intertidal in some locations; widely distributed in the north western and north eastern Atlantic, often abundant and zone-forming at low water.
Text source: Algaebase