Comment on the life cycle and nature of a fern prothallus.
The life cycle of fern (Dryopteris) clearly shows the alternation of generation.The gametophytic stage (n) alternates with the sporophytic stage (2n) figure given shows its complete life cycle.
Prothallus The prothallus of the fern is multicellular, free living, thalloid, haploid and autotrophic structure. it develops from the spores produced by sporophyte after reduction division.
These spore germinate with a germtube with an apical cell and forms a filament of 3-6 cells and one or two rhizoids at the base which alter develops into gametophytic plant.