Zentrische Diatomee; Oogamie. Aus männlich determinierten Zellen gehen durch einige Differenzierungsteilungen Spermatogonien hervor. In diesen entwickeln sich je vier eingeißelige Spermien. Oogonien entstehen direkt aus vegetativen Zellen. Nach der Befruchtung schwellen die Zygoten zu Auxosporen an. Aus der Auxospore entwickelt sich die Erstlingszelle.

The centric diatom Attheya decora reproduces sexually by oogamy. The monoecious clones produce sperms as well as eggs. Spermatogonia arise from male determined cells by a few differentiating mitosis. By two meiotic nuclear and cell divisions four uniflagellate sperm cells are formed within a spermatogonium. Oogonia develop directly from vegetative cells undergoing a considerable lengthening of the cell. The first of both nuclear divisions is accompanied by a cytokinesis, resulting in two egg cells per oogonium. After fertilization the zygotes are transformed into auxospores by swelling. From the auxospore the initial cell is formed by two consecutive metagamic mitosis with subsequent secretion of two thecae.