22 



GENUS PALLAVICINIA 



the four original peripheral cells of the antheridium have each divided at 

 least once (Fig. 10, G). The first division in the central cells is a transverse 

 one, quickly followed by a vertical division, so that whether in longitudi- 

 nal- or cross-section, the central cells are arranged quadrant-wise (Figs. 

 10, H, ii, B). The subsequent divisions follow rapidly, but without any 



A-D. P. radiculosa; E-G, P. Levieri. 



A-C. Cross-section of young antheridia. 



D. Longitudinal section of a nearly ripe antheridium. 



E-G. Longitudinal sections; H, transverse section. 



