The reproductive structure found in the life cycles of both mosses and ferns is called a sporophyte.

Here's a breakdown:

* Mosses: Mosses have a dominant gametophyte generation, meaning the plant we see is the haploid gametophyte. The sporophyte is a small, stalk-like structure that grows out of the gametophyte.

* Ferns: Ferns also have a dominant gametophyte generation (although less noticeable than in mosses), but their sporophyte is the larger, familiar plant we recognize. The sporophyte produces spores in structures called sporangia, which are located on the underside of the fern fronds.

Both mosses and ferns exhibit alternation of generations, meaning they have distinct haploid (gametophyte) and diploid (sporophyte) stages in their life cycle.