The alternation of generation is a feature shown in mosses and some other plants, but not in fungi or grasses or conifers.
Alternation of generation refers to a life cycle where an organism alternates between a multicellular diploid (2n) phase called the sporophyte, and a multicellular haploid (n) phase called the gametophyte. In mosses, the sporophyte is a stalk-like structure that grows out of the gametophyte and produces spores, while the gametophyte is a small leafy structure that produces gametes. The spores produced by the sporophyte develop into a new gametophyte, completing the life cycle.
In fungi, there is no alternation of generation. Most fungi have a haploid-dominant life cycle, meaning that they spend most of their life cycle in the haploid phase. They produce haploid spores that can grow into new haploid individuals, without the need for a diploid phase.
In grasses and conifers, the life cycle is dominated by the diploid sporophyte phase, with the haploid gametophyte phase being reduced to small structures that produce gametes. These gametes fuse to form a diploid zygote, which develops into a new sporophyte.
So, in summary, mosses exhibit alternation of generation, while fungi, grasses, and conifers do not.