Rosenvingiella polyrhiza

Green rock scum

Authority: (Rosenvinge) P.C.Silva

Thallus is an unbranched, narrow solid cylinder (to 80 μm wide), ranging in color from light green to dark green. Mature thalli are pluriseriate and reach at least several cm in length (~1 in). They are sometimes constricted at intervals. Reproductive cells, which can contain numerous male (smaller) or female (larger) gametes, can be seen on the thallus surface.

Habitat

The species is found on rock at or above high water mark and may occur mixed with species of Prasiola. This species can withstand long periods out of the water in protected to semi-exposed habitats. It is frequently seen as a wide band in the high intertidal of the Aleutian Is.