Final answer:
Gametes in mosses are produced during the gametophyte phase, which is the dominant and recognizable green vegetative stage of their life cycle, contrasting with ferns where the gametophyte is smaller and less dominant compared to the leafy sporophyte.
Step-by-step explanation:
Mosses and ferns both exhibit a life cycle that includes an alternation of generations, which alternates between a haploid gametophyte and a diploid sporophyte. For mosses, the sporophytes are made in the sporophyte phase, and gametes are produced in the gametophyte phase. In ferns, the sporophyte is the more prominent stage and is free-living, whereas in mosses the gametophyte is the more prominent and developed stage, often observable as the green carpet of vegetation in moist environments.
Mosses, being bryophytes, have a gametophyte stage that is green, photosynthetic, and forms the most recognizable part of the plant such as the leafy structures which are evident on damp surfaces in forests. In this life stage, the gametes are produced which will unite to form the sporophyte.
The resulting sporophytes are then responsible for the production and dispersal of spores. On the other hand, the fern life cycle features a dominant sporophyte stage where the familiar, leafy fronds are produced. These contain sporangia that release spores, which then develop into smaller, generally free-living gametophytes that produce the necessary gametes for fertilization and continuation of the cycle.