Spore-bearing cases on the underside of a fern frond. Ferns reproduce by spores rather than seed.
Q: I received a potted fern as a gift from a friend, and it has done well in my home for over a year. But now it has what looks like a fungus on the bottom side of the leaves. Is there anything I can apply to prevent this from killing my plant?
A. The growths on your fern are not from a fungus. They are fern spore cases and are not harmful to the plant. Unlike flowering plants, ferns reproduce by spores rather than seed. Spore cases (sporangia) are produced on the bottom side of the fronds; each case contains numerous spores. Gardeners sometimes mistake the spore cases for either a disease or insect pest but these are normal reproductive structures for ferns.