Thin ruffled blades 15-30 cm tall growing in groups from small discoid holdfast; blade composed of a single layer of cells; gray-green to brownish purple. Resembles crumpled cellophane when dry. Sporophyte stage ("conchocelis") is a microscopic filament growing into mollusc shells.
Common, high intertidal zone. No other conspicuous alga occurs higher on the shore; protected & exposed outer coast.Geo Range: Alaska to Baja