Saccorhiza polyschides (Lightfoot) Batters
Description: Thallus laminate, yellowish to dark brown, generally to 3 m long; holdfast large, hollow and covered in smooth warts (below, bottom; thus "Sea Hedgehog") when mature, giving rise to a flattened oar-like stipe with beautifully symmetrical frilly "wings" (below, left and right) with a single twist at the base. Stipe forming a single digitate fronds with irregularly lacinate "digits", these are dotted with groups of hairs.
Habitat: lower intertidal and shallow subtidal. Generally filling in "holes" in shallow-water Laminaria digitata forests. This is an annual kelp, essentially an opportunist that colonises any vacant space in the forest, but cannot compete with the dominant species.
Distribution: widely distributed in Britain, Ireland, France, Spain and Portugal. South to the Canary Islands, Morocco, Ghana and Mauritania.
Key characteristics: Hedgehog-like base (absent in very young plants), flattened oar-like stipe with frilly edges at base. A flattened stipe of this kind is not found in any other kelp.