. Elementary botany. Botany. (EDOGONIUM. 149 opening through which the spermatozoid entered to fecundate the egg. 313. Dwarf male plants.—In some species there will also be seen peculiar club-shaped dwarf plants attached to the side of the oogonium, or near it, and in many cases the end of this dwarf plant has an open lid on the end. 314. Antheridium.—The end cell of the dwarf male in such species is the antheridmm. In other species the spermatozoids are developed in different cells (antheridia) of the same thread which bears the oogonium, or on a different thread. 316. Zoospore stage of cedog
. Elementary botany. Botany. (EDOGONIUM. 149 opening through which the spermatozoid entered to fecundate the egg. 313. Dwarf male plants.—In some species there will also be seen peculiar club-shaped dwarf plants attached to the side of the oogonium, or near it, and in many cases the end of this dwarf plant has an open lid on the end. 314. Antheridium.—The end cell of the dwarf male in such species is the antheridmm. In other species the spermatozoids are developed in different cells (antheridia) of the same thread which bears the oogonium, or on a different thread. 316. Zoospore stage of cedogonium.—The egg after a period of rest starts into active life again. In doing so it does not develop the thread-like plant directly as in the case of vaucheria and spirogyra. It first divides into four zoospores which are exactly like the zoogonidia in form. (See fig. 152.) These germinate and develop the thread form agaiii. This is a quite re- markable peculiaritj' of cedogonium when compared with either vaucheria or spirogyra. It is the introduction of an intermediate stage between the fertilized egg and that form of the plant which bears the sexual organs, and should be kept well in mind. 316. Asezual reproduction.—Material for the study of this stage of cedo- gonium is not readily obtainable just when we wish it for study. But fresh plants brought in and placed in a quantity of fresh water may yield ' suitable material, and it should be examined at intervals for several da}-s. This kind of reproduction takes place by the formation of zoogoiiidia. The entire contents of a cell round off into an oval bod}', the wall of the cell breaks, and the zoogonidium escapes. It has a clear space at the small end, and around this clear space is a row or crown of cilia as shown in fig. 146. By the vibration of these cilia the zoogonidium swims around for a time, then settles down on some object of support, and several slender holdfasts grow out in the form of short rhizoids which
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