Erythrodermis traillii (Batters) Guiry & Garbary
Also known as Phyllophora traillii Holmes ex Batters and Erythrodermis allenii
Description: Cartilaginous, light reddish-brown fronds, to 30 mm long, with short cylindrical stipes from small discoid holdfasts. Blades flat, simple with parallel sides or dichotomously divided, sometimes with the appearance of an evanescent midrib (see the third plant from the left above). Reproductive structures (male and female) borne in small fringing leaflets. Tetrasporangia on a small crust.
Habitat: On shady rocks and pool margins, often in caves and associated with sponges, lower intertidal and shallow subtidal, widely distributed.
Similar species: Rhodymenia delicatula.