Brown Algae (Phaeophyta)
The brown algae are almost exclusively marine, the few fresh water species being quite rare.
One kind, Heribaudiella, is of particular note. It forms a relatively large disc shape crust of dark color on stones in rapidly flowing upland streams. The pigments of Phaetophytes include chlorophyll A and C, carotene and xanthophylls, including fucoxanthin. The last mentioned pigment predominates to give the characteristic brown color.
Food reserve is maintained in brown algae in forms of sugar.