Cytological Study of Oedogonium

Abstract

In O. grande the mitotic process, especially the behavior of chromosomes, shows a remarkable resemblance to that of higher plants. The number of chromosomes is 13, an uneven number. In spermatogenesis all important phases of mitosis in the formation of antheridia and sperms have been traced. In mitosis of the antherid-ial cell, the figure is oriented along the horizontal axis, while the cell division is to be transverse. This seems to be an unusual condition in cell division and has never been described in Oedogonium. Spermatogenesis in the dwarf male of O. nebraskense was also followed. There are two types of oogenesis, one with a suffultory cell (O. nebraskense) and the other without (0. americanum). The behavior of the nucleus in oogenesis in these species is described. Zoospore formation is described in an unknown species. The escape of the zoospore takes only a few minutes. Of the factors which stimulate the formation of zoospores, change of temperature seems to be the most effective.