. Botany of the living plant. Botany. SCHIZOPHYTA 457 Oscillatoria is a filamentous type, which is common on damp walls and rocks. Its pale green filaments show slow swinging movements, hence the name (Fig. 390). They consist of disc-shaped cells, which multiply by division. In some of the larger forms granules of irregular form are found in each cell, giving the staining re- actions of chromatin, and dividing before division of the cell, but without a definite nuclear spindle. The filaments may break up at any point into shorter lengths, and are unattached. In other cases special cells (heter
. Botany of the living plant. Botany. SCHIZOPHYTA 457 Oscillatoria is a filamentous type, which is common on damp walls and rocks. Its pale green filaments show slow swinging movements, hence the name (Fig. 390). They consist of disc-shaped cells, which multiply by division. In some of the larger forms granules of irregular form are found in each cell, giving the staining re- actions of chromatin, and dividing before division of the cell, but without a definite nuclear spindle. The filaments may break up at any point into shorter lengths, and are unattached. In other cases special cells (heterocysts) occur at intervals in the filaments, which appear to determine their breaking up into shorter lengths, as in -t. Fig. 390. A, Oscillatoria priiwcps : a terminal portion of a filament; b, portions from the middle of a filament, properly fixed and stained ; /, cells in di\'ision. ( x loSo). B, Oscillatoria Frodichii. (X540). S. Nostoc or Rivularia. Some of these fission-Algae take part in the formation of Lichens : thus Collema has Nostoc as its Algal constituent. Others, such as Anabaena, lead an endophytic life, contributing probably to an irregular nutrition, as in the roots of Cycads. In the establishment of the new Flora of the sterilised Island of Krakatoa (p. 295), blue-green Algae were among the first colonists, taking their part in the preparation of an organic soil for larger developments to follow. Certain of these Algae allied to Anabaena often appear suddenh' in large quantities on the surface of fresh water, causing the phenomenon known as " water bloom," or the " breaking of the ; One of these, with a deep red colour [Trichodesmiwn erv- thraeim), floats in ocean-waters, and becomes prominent when massed together by wind and tidal streams. It has thus attracted attention in various oceans, and has given its name to the " Red ;. Please note that these images are extracted from scanned page images that may have been digi
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