only thallophyte in plant kingdom (thallus (undifferentiated plant body) as body)
thallus is pigmented (unpigmented in fungi (mycelium))
diversity in thallus (thalloid body of algae)
maximum diveristy in green algae
can be unicellular (hlamydomonas and chlorella) (supposed to be in protista), colonial (Volvox, Eurodina), filamentous (Spirogyra, Oedogonium, Ulothrix, Chladophora (branched)), and multicellular (polysiphia, fucus, chara)