Answer:
sporophyte
Explanation:
The fern is an asexual spore-producing plant. Therefore, it represents the phase called sporophyte. At certain times, on the lower surface of the leaves of ferns dark spots called serums form. The emergence of sera indicates that ferns are in breeding season - in each serum numerous sporophytes are produced.
When the spores mature, the serums open. Then the spores fall into the damp soil; each spore can germinate into a protalo, that heart-shaped little plant shown in the scheme below.
