Delicately membranous, rose-pink fronds with an elongate fan-shaped outline, margins distinctly frilly, to 40 mm or, exceptionally, to 1 m, sessile or shortly stipitate (< 2 mm long). Frond veinless, undivided or deeply subdichotomously divided to the base; apices blunt or rounded, often ribbon-like. Gametophyte plants form rounded spots to 5 mm in diameter whilst tetrasporphyte plants form characteristic elongated spots.

Annual, intertidal pools in winter and early spring and in the subtidal (15 m) on cobble or other mobile surfaces and on bedrock in the lower parts of kelp forests from spring to mid-or late summer; widely distributed, frequent. Most obvious in spring and early summer.

Delicate, veinless, translucent fronds with and elongated fan shape and with elongate or rounded spots (reproductive sori) scattered regularly on most plants. Extremely large plants to 1 m long have been known for many years from NE Ireland; there is no explanation for this phenomenon.

Cited from: www.algaebase.org