What structure in ferns is diploid?

In ferns, the diploid structure is the sporophyte, which is the dominant phase of their life cycle. The sporophyte consists of the leafy fronds and the underground rhizome. It produces spores through meiOSis in specialized structures called sporangia, which are typically located on the undersides of the fronds. These spores are haploid and develop into the gametophyte stage, completing the life cycle.