How is alternation of generations different in ferns and pines?
In the ferns the two generations (diploid sporophyte and haploid gametophyte) exist as separate plant bodies; the gametes are produced by mitosis in the haploid prothallus gametophyte, water is needed for fertilisation and both generations are able to photosynthesize. In pines (gymnosperms) the dominant generation of the gymnosperm life cycle is the long lived sporophyte, and the gametophyte generation is inconspicuous. The male gametophyte, the pollen grain, is not dependent on water for sperm transfer. The female gametophyte, the ovule, is nutritionally dependent on the sporophyte.
