(family Fucaceae, order Fucales)
A genus of brown seaweeds which resemble Fucus, but which can be distinguished by the absence of a midrib. The thallus is typically flattened and straplike, and air bladders are usually present; it may reach several metres in length. Spores develop in yellowish receptacles, resembling sultanas, borne on short stalks arising from either side of the fronds. The only British species is A. nodosum. See egg wrack.
Subjects: Plant Sciences and Forestry.