In which one of the following, the male and female gametophytes don't have free-living independent existence?

Step-by-step solution

In Pteris (also Dryopteris), the spore germinates to produce the prothallus. The prothallus is a small, green, flat, surface loving, thallus-like object. It is monoecious and bears sex organs on the ventral side. The antheridia (male sex organs) arise among the rhizoids towards the posterior side of the prothallus and are emergent. The archegonia develop in central cushion behind the apical notch. In these plants, male and female gametophytes do not have free living independent existence. All species of Polytrichum