This Athyrium species has one extra level of frond division than seen in described species of Athyrium of Eastern North America. That is to say, the leaflet is essentially the usual, but small, frond of an Athyrium.
This species has been observed at
Walking a trail after blacklighting at Long Pine Key
My blacklighting observations from LPK before sunrise:
https://www.inaturalist.org/observations?on=2024-04-28&order=asc&order_by=observed_on&place_id=any&project_id=blacklighting-florida&user_id=joemdo
Video showing the lights I use for a typical setup:
https://youtu.be/tavmTa7WoPk
Blacklighting project for Florida: https://www.inaturalist.org/projects/blacklighting-florida
More details in general about my 2024 City Nature Challenge:
https://www.inaturalist.org/journal/joemdo/93673-city-nature-challenge-2024