Chromophycota

(botany) A division of the plant kingdom comprising nine classes of algae ranging in size and complexity from unicellular flagellates to gigantic kelps; distinguished by the presence (in almost all) of chlorophyll c to complement chlorophyll a, and usually having brownish or yellowish chloroplasts. Also known as Chromophyta.

A division of the plant kingdom (also known as Chromophyta) comprising nine classes of algae: Bacillariophyceae (diatoms), Chrysophyceae (golden or goldenbrown algae), Cryptophyceae, Dinophyceae (dinoflagellates), Eustigmatophyceae, Phaeophyceae (brown algae), Prymnesiophyceae, Raphidophyceae, and Xanthophyceae (yellow-green algae). Some of these classes are closely related, while others stand so far apart that they are sometimes assigned to their own divisions. The chief unifying character is the presence of chlorophyll c rather than chlorophyll b as a complement to chlorophyll a (although only chlorophyll a is present in Eustigmatophyceae). The chloroplasts are usually brown or yellowish because of large amounts of β-carotene and various xanthophylls, many of which are restricted to one or more classes. In most classes, motile cells bear two unequal flagella, one of which may be almost completely reduced and at least one of which bears two rows of hairlike appendages. Algae range in size and complexity from unicellular flagellates to gigantic kelps. See also Algae; Bacillariophyceae; Chrysophyceae; Cryptophyceae; Dinophyceae; Eustigmatophyceae; Phaeophyceae; Prymnesiophyceae; Xanthophyceae.