Figure 4.

Development of an antheridium from an antheridium apical stem cell. Antheridia after the third (a), fourth (b), fifth (c), sixth (d) and seventh (e) cell divisions of an antheridium apical stem cell are shown. The thicker lines between cells in the drawings indicate the cell division planes formed by cell divisions of the antheridium apical stem cell and the thinner lines indicate other cell division planes. Numbers from 1 to 7 indicate the first to the seventh cell divisions of the antheridium apical stem cell. Scale bars, 20 µm.