Here's why:

* Fern Life Cycle: Ferns have a distinct life cycle that alternates between a haploid gametophyte generation and a diploid sporophyte generation.

* Sporophyte: The familiar fern plant you see (with fronds, roots, and stems) is the sporophyte generation. This generation is diploid, meaning it has two sets of chromosomes.

* Gametophyte: The gametophyte generation is a small, heart-shaped structure that produces gametes (sperm and egg). This generation is haploid, meaning it has only one set of chromosomes.

Therefore, the fern cells you see (fronds, stems, etc.) are part of the diploid sporophyte generation.