Porphyra umbilicalis is a small alga normaly with irregularly shape and polythene-like texture that first it’s greenish and then, when grown-up, become purplish-red and light to dark reddish-brown. A common form is where the blade expands around the holdfast and appears to be a little cabbage.

This specie attaches to rocks via a minute discoid hold-fast, rather in shaded areas.  It is highly able to resist to prolonged periods of drying and contains natural ultraviolet (UV) sunscreens.

Besides, it has a short life time, although it reproduces fast and it can be found on different periods of the year, so it exists in massive scale.