Chrysophyceae

(botany) Golden-brown algae making up a class of fresh- and salt-water unicellular forms in the division Chrysophyta.

A relatively large and diverse class of algae in the chlorphyll a–c phyletic line (Chromophycota). In protozoological classification, these organisms constitute an order, Chrysomonadida, of the class Phytomastigophora. Some workers align Chrysophyceae (golden or golden-brown algae) with Bacillariophyceae (diatoms) and Xanthophyceae (yellow-green algae) in the division Chrysophyta. See also Chromophycota.

Chrysophytes typically are flagellate unicells, either free-living or attached, and solitary or colonial. There are, however, ameboid and plasmodial forms, solitary or colonial nonflagellate cells, filaments, and blades. Fresh-water forms, which are usually found in cold clear water, are more common than marine forms.

Asexual reproduction in unicellular forms is by longitudinal binary fission, autospores (nonflagellate cells that are miniatures of the parent), or zoospores, and in multicellular forms by fragmentation or zoospores. See also Algae; Bacillariophyceae; Bicosoecida; Choanoflagellida; Chrysomonadida; Xanthophyceae.