Fig. 12. Post-fertilization in Pterothamnion squarrulosum where the auxiliary cell has cut off an apical cell to receive the zygote (Athanasiadis & Kraft 1994).
Fig. 13. Post-fertilization in Antithamnionella spirographidis where the carpogonium has developed an extension tube to transfer the zygote (Athanasiadis 1996, p. 121).