In some areas you will find a red algae growing on Ascophyllum nodosum. This algae is Polysiphonia lanosa and it is an epiphyte (ehpee-fight). An epiphyte is a plant that grows on another plant, but is not a parasite. It is a filamentous algae and grows on Ascophyllum exclusively in short, dark red bushy patches. You are more likely to find epiphytic algae growing on Ascophyllum on protected shores rather than wave-exposed shores. Why would an epiphyte choose a protected shore?