On the shore you will see the blade phase of Porphyra umbilicalis.
- the blade is light to dark reddish-brown
- the blade can be very variable in shape and form
- it is only one cell layer thick and translucent
- it develops from a very small disc called the holdfast
- a common form is where the blade expands around the holdfast and appears pleated or resembles a rosette or a little cabbage
- individuals are usually about 5–10 cm tall