オゴノリ

The liberation of tetraspore in Gracilaria verrucosa was studied in detail with special reference to the structure and abnormal division in the contents of a packet of extruded tetraspores. 1) An extruded mass of tetraspores is surrounded by some mucilaginous substance about three to several microns thick, and is joined to the plant surface. Accordingly, spores remain on the frond similarly to Sargassum eggs. Inside the mucilaginous substance a thin vesicle envelops the four spores. When the vesicle became empty, methylene blue solution makes its presence and feature evident. Much the same structure of the extruded tetraspores as above may be expected for other red algal species not only G. verrucosa. 2) Around each spore, just after the release from a thin vesicle, a thin layer of mucilage is observed, by means of which spore will presumably attach to the substratum. Set freed spores sink together in a group scarcely changing any mutual position in still water, very likely they are embedded in some gelatinized substance. 3) In damp-dried materials packets of tetraspores are ready to extrude, but when kept in that condition too long the progress of liberation becomes slack and the spores seem less vital in appearance. After extrusion from the frond it takes twenty seconds to two and a half minutes before the spores are released from the thin vesicle, ellipsoid or comma shaping. 4) Sometimes there were observed abnormal divisions in the contents of a packet without producing four spores. When only three spores were produced, one of them was evidently large in size and had two nuclei, but other two spores has no significant feature in appearance. In tetrasporangium the arrangement of four spores is cruciate, but instance of tetrahedral has been observed as well.