The
Chromista are a
eukaryotic supergroup, probably
polyphyletic, which may be treated as a separate
kingdom or included among the
Protista. They include all
algae whose
chloroplasts contain
chlorophylls a and
c, as well as various colorless forms that are closely related to them. These chloroplasts are surrounded by four membranes, and are believed to have been acquired from some
red algae.