Ferns

Like all plants, the life cycle of ferns is characterized as having an alternation of a gametophyte phase and a sporophyte phase. A typical fern sporophyte is the large, familiar plant seen in nature. Its cells have the unreduced number of chromosomes, usually two sets. Most fern gametophytes are not seen in nature. A typical gametophyte is about 0.4 in (1 cm) in diameter, multicellular, flat, heart-shaped, and green. Its cells have the reduced number of chromosomes, usually one set.

Interestingly, the gametophyte and sporophyte are about equally dominant in the life cycle of ferns. In contrast, the gametophyte is dominant in the more evolutionarily primitive bryophytes (mosses, liverworts, and hornworts), whereas the sporophyte is dominant in the more evolutionarily advanced seed plants.