SIZE:
40 cm to 90 cm, depending on the species.
LIFE EXPECTANCY:
3 to 5 years (toothed wrack), up to 15 years (bladder wrack).
LIFE CYCLE:
Rockweeds are long-lived. They grow from the tips of their fronds. New branches are added to each tip of the existing ones. If the frond is lost, regeneration can also take place from the holdfast.
Depending on their species, the plants can bear either one type of sex cell or both. In all cases, the receptacles at the end of the fronds release eggs and sperm in spring. After fertilization, the new individual settles to the bottom and begins to grow.