The phenomenon where a plant's life cycle alternates between a haploid gamete-producing phase and a diploid spore-produc
NCERT Class 11 Biology clearly defines that the life cycle of higher plants strictly alternates between a diploid sporophytic generation and a haploid gametophytic generation. The lengths of these phases, and whether they are free-living or dependent on each other, vary wildly among the different plant divisions. This fundamental botanical phenomenon is officially termed 'alternation of generation'.
Ref: NCERT Class 11 Biology > Chapter 2: Biological Classification > 2.4 Kingdom Plantae