erect red algae
Fan-like branching red algae with channeled fronds. Central/main branch tends to be thicker and triangle-like.
Photo from Ignacio Bárbara via WORMS
Other images:
Distinguishing features: Has channeled fronds. Does NOT have a blue iridescence underwater and in some lighting. When reproductive, can be covered in small cysts/bumps, resembling grape pips.
Easily confused species and differentiation: Chondrus Crispus (CHCR) Chondrus has a flat stipe/thalli, although the edges of the blades might be curly. Mastocarpus stipes/thalli are curled. See here for the definitive guide.
Extended Description: Red algae with fan-like dichotomous branching. Fronds are thick and leathery. It is often twisted. Can be found intertidally or in the shallow subtidal.