Genus: Highly flattened; pellicle firm; body form constant (Kudo, 1966).
Chloroplasts small, discoid, pyrenoids usually absent; most species flat and leaf-shaped;
often with ridges or fins running helically or longitudinally (Illustrated Guide, 1985).
Phacus pleuronectes, x 400, x 640, Uruguay Nov. 1999, photo by Yuuji Tsukii
Phacus pleuronectus, x 400, x 640, Uruguay Nov. 1999, photo by Yuuji Tsukii