Final answer:
The male gametophyte of Mnium is called spermatazoids and they are multiflagellated corkscrew-shaped sperm cells that are chemically attracted to the female gametophyte. The female gametophyte is larger and produces a single egg, which is fertilized by the spermatazoids.
Step-by-step explanation:
The male gametophyte of Mnium is called spermatazoids.
Spermatazoids are multiflagellated corkscrew-shaped sperm cells that are released from the male gametophyte when the microspore wall is broken. These spermatazoids are chemically attracted to the female gametophyte. The male gametophyte is much smaller than the female gametophyte and exhibits endosporic development, meaning that it develops within the spore case of the megaspore.
The female gametophyte, on the other hand, is substantially larger than the male gametophyte. It produces a single archegonium with a single egg. When the spermatazoids swim to and fertilize the egg, a zygote is formed, which eventually develops into a new sporophyte plant.