By means of column (CC), thin-layer (TLC), high-performance liquid (HPLC) and ion exchange chromatography (IEC) the authors investigated the antenna pigments (chlorophylls, carotenoids, phycobiliproteins). The phytochromes were also studied in the five water-ferns of Azolla genus (A. caroliniana, A. filiculoides, A. imbricata, A. microphylla, A. pinnata). Three groups of antenna pigments (chlorophyll a and b, 11 carotenoids, 4 phycobiliprotein pigments) absorbing rays of PAR beams from the environment are present in this water-ferns and chromatic adaptation can exist in the conditions of the water. In the tissue of water-ferns and in nostocean cyanobacteria as photobiont the presence of phytochromes was found.