Elementary botany . Fig. 159. Coleochaete soluta ; at left branch bearing oogonium (oog); antheridia (nut); egg inoogonium and surrounded by enveloping threads ; at center three antheridia open, and onespermatozoid ; at right sporocarp, mature egg inside sporocarp wall. cell elongates into a slender tube which opens at the end to form a channel through which the spermatozoid may pass down to the egg. The egg is formed of the contents of the cell (fig. 159). Several oogonia are formed on one plant, and in such a IS55T plant as C. scutata they areformed in a ring near themargin of the disk. 328.
Elementary botany . Fig. 159. Coleochaete soluta ; at left branch bearing oogonium (oog); antheridia (nut); egg inoogonium and surrounded by enveloping threads ; at center three antheridia open, and onespermatozoid ; at right sporocarp, mature egg inside sporocarp wall. cell elongates into a slender tube which opens at the end to form a channel through which the spermatozoid may pass down to the egg. The egg is formed of the contents of the cell (fig. 159). Several oogonia are formed on one plant, and in such a IS55T plant as C. scutata they areformed in a ring near themargin of the disk. 328. Antheridia.—In certain of the cellsof the plant divide into foursmaller cells, and each oneof these becomes an antheri-dium. In C. soluta the an-. Fig. sporocarps still Sporocarp ruptured b ysurrounded by thallus. growth of egg to form cell theridia grow out from theThallus finally decavs and mass. Cells of this sporo- . sets sporocarp free. phyte forming zoospores. end ol terminal cells in the Figs. 160, 161. C. scutata. form of short flasks, some- times four in number or less (fig. 159). A single spermatozoid is formedfrom the contents. It is oval and possesses two long cilia. After swim- 15^ MORPHOLOGY. ming around it passes down the tube of the oogonium and fertilizes the egg- 329. Sporocarp.—After the egg is fertilized the cells of the threads nearthe egg grow up around it and form a firm covering one cell in envelope becomes brown and hard, and serves to protect the egg. Thisis the fruit of the coleochsete, and is sometimes called a sporocarp(spore fruit). The development of the cell mass and the zoospores from theegg has been described above. Some of the species of coleochaete consist o
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