1. Sori (small brown spots) upon the underside of the fronds contain numerous spore-bearing bodies known as sporangia (x1/2). 2. A typical sorus (x60) containing sporangia. 3. Sporangium (x200) containing spores. 4. Gametophyte (x3) (the thin heart-shaped plant) develops from the spore. Sex organs, corresponding in general function to the stamen and pistil of flowering plants, are upon the underside. 5. From the gametophyte develops the fern plant that one sees, known as the sporophyte (x1/10).