Fern Friday: Spores or Seeds

Resurrection fern (Pleopeltis michauxiana), like all ferns, reproduces via wind-borne spores – not seeds. The “warty” spots that you see on the resurrection fern pictured above are made by the spore cases (sporangia) on the underside of the fronds.

The underside (abaxial surface) of resurrection fern is covered in tiny scales. The scales slow dehydration and facilitate the absorption of water. Over the course of 5 days, resurrection ferns can lose 75% of their water content.

When moist conditions return, resurrection ferns open the scales on the undersides of their fronds to imbibe moisture, unfurl themselves, and “green up” …

The scientific name for resurrection fern once was Polypodium polypodioides, and you still will see that “old” name in use in older texts and on the web. The next scientific name given to this fern was Pleopeltis polypodioides. That name now is associated with tropical resurrection fern, which is known from only one population in Florida located on Key Largo. Tropical resurrection fern is distinguished from “regular” resurrection fern by the presence of scales on the top (adaxial blade) of its fronds.

The genus name, Pleopeltis, comes from the Greek words pleos (many) and pelte (shield) and refers to the scales that grace the underside of “regular” resurrection fern and both sides of tropical resurrection fern. The species name, michauxiana, honors French royal botanist Andre Michaux (1746 – 1803), who explored Spanish east Florida.

The spores eventually will be released to the winds …