1) A peculiar purple vactuolar pigment of the terrestrial alga Zygogonium sp. was examined, and the chemical and physical properties of this pigment matched generally that reported by Alston (1958).
2) It seems that the purple or reddish brown vacuolar pigments of terrestrial algae have an effect of protection against injurious strong intens of natural sun light especially of U. V.
3) The chlorophyll content of Zygogonium, Hormidium and Trentepohlia mostly ranges 0.04-8.64 percent of the dry weight. The chlorophyll constituted about 0.2 percent of the dry weight of the cells of yellowish orange form of Trentepohlia, 7 percent of the dry weight of the cells of Hormidium and 1 percent of the dry weight of the cells of Zygogonium.
4) A differentiation of photosynthetic patterns viz. shade-type (inhibited under strong intensity of the sun light) and sun-type (non inhibited) has been recognized in aerial alga Trentepohlia and in terrestrial algae Zygogonium and Nostoc.
5) Certain aerial and terrestrial algae such plants as Trentepohlia and Zygogonium show a conspicuous tolerance against hypertonic condition (0.2-0.8 mol of sucrose solution and corresponded concentration of marine water).