Downy maiden fern (Thelypteris dentata) was volunteering along the foundation of the Ryall house at the South Prong Slough when we visited on 5/15/2022. Also known as downy shield fern, this attractive tropical/subtropical fern is naturalized throughout Florida, including along the Herb Kale Nature Trail at the Oslo Riverfront Conservation Area. It is native to the tropical and subtropical Pacific and can be invasive elsewhere
Identifying characteristics, seen above, include the pinnatifid (pointed) apex (tip), narrower pinnae (leaflets) at the base, and a distinctive purplish brown petiole (leafstem) shown below …
Fertile fronds are longer and have more compact with pinnae and round golden sori (clusters of spore cases).
Winds spread the spores to moist places. The University of Florida Assessment of Non-Native Plants in Florida’s Natural Areas advises caution when planting this fern in central and south Florida.