. Botany of the living plant. Botany. CHAPTER XXV. GREEN ALGAE [CHLOROPHVCEAE). The Brown and Red Algae form natural and coherent groups of plants, characterised by their colour, but more particularly by their propa- gative organs. Green Algae are a more heterogeneous assemblage of forms. Some are marine : others live in fresh water. Some are uni- cellular, some colonial (Protococcales, Volvocales) : others, which are multi- cellular, consist of a simple filament, with various degrees of its branching (Ulothricales) ; or they may form widened fiat expansions (Ulvaceae) : others again are coeno
. Botany of the living plant. Botany. CHAPTER XXV. GREEN ALGAE [CHLOROPHVCEAE). The Brown and Red Algae form natural and coherent groups of plants, characterised by their colour, but more particularly by their propa- gative organs. Green Algae are a more heterogeneous assemblage of forms. Some are marine : others live in fresh water. Some are uni- cellular, some colonial (Protococcales, Volvocales) : others, which are multi- cellular, consist of a simple filament, with various degrees of its branching (Ulothricales) ; or they may form widened fiat expansions (Ulvaceae) : others again are coenocytic, not being partitioned into cells (Siphonales), or only partially septate (Siphonocla- diales). The variety of their form and structure is matched by the diversity of their propagation. Some multiply by simple fission [Proto- coccus viridis, Fig. 328) : others undergo conjugation of equal, non- motile cells (Conjugatae); but most of them produce motile zoospores and gametes, the latter showing in more than one natural series evidence of a progressive sexual differen- tiation (Ulothricales, Siphonales, Fig. 335). The effect of a general study of them is to suggest that they may all represent steps in advance from the Flagellatae ; and that they represent many distinct lines in which an increasing complexity of development of their encysted phase, and a differentiation of sex have been independently achieved. 390. Fig. 328. Cells of Protococcus, some isolated, others resulting from recent division, are still coherent. ( x 730.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bower, F. O. (Frederick Orpen), 1855-1948. London, Macmillan
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