(Isokontae, green algae) A large division containing the green-pigmented * algae, commonly found in freshwater or moist terrestrial habitats. The green algae show a wide range of form and of sexual and asexual reproductive methods. They contain chlorophylls a and b, carotenes, and xanthophylls, store food reserves as starch, and always have cellulose cell walls. In these respects and in their ultrastructure they resemble the bryophytes and tracheo-phytes more than any other algal division (except possibly the Charophyta, when these are given divisional rank). Some classifications separate the division into the two classes, Chlorophyceae and Charophyceae. Another system elevates the Charophyceae to divisional rank, the * Charophyta, and divides the remainder into four classes: the * Chlorophyceae , * Oedogoniophyceae , * Bryopsidophyceae , and * Zygnemaphyceae. |
