Dark brown, to 2 m in length; with a claw-like, conical hold fast, a rough, rigid stipe which generally sticks up out of the water, and is covered in epiphytes when older, and a laminate blade to 1.5 m long dividing into finger-like segments.
Habitat:
Common at extreme low water in wave-exposed areas, and in the sub tidal in optically clear water growing on rock to a depth of 32 m. Forms extensive closed communities at depths of 0-24 m.
Distinguishing features:
Stipe is rugose (rough) when older, circular in cross ection, and snaps easily when bent; the hold fast is conical; there are usually lots of ephytic red algae growing on the older stipes, particularly Palmaria palmata; the old fronds are cast off in spring and new ones grow below for a time; in
Distribution:
All coasts of Britain and Ireland.
Usage:
Dredged in Norway for alginate production, in Ireland cast-up stipes used to be collected for alginate production in Scotland but collection has ceased in recent years.Laminaria digitata the plants are darker in colour, the stipe is generally shorter, narrower. In Saccharina latissima (formerly Laminaria saccharina) the blade is undivided and has regular, small depressions.
