Swamp fern (Telmatoblechum serrulatum) is prevalent in moist places at the Cypress Bend Community Preserve (CBCP), just like at the Oslo Riverfront Conservation Area (ORCA). It is pictured above in dappled shade along the CBCP trail.
Toothed midsorus fern is another common name for this plant. A sorus is a cluster of sporangia, the structures that produce and contain spores, and, on this fern, the sori are found along the midrib in a distinctive pattern.
The species name, serrulatum, means small-toothed and refers to leaf margins. At a glance, you might not notice these tiny teeth
The scientific name for this fern once was Blechnum serrulatum. Based on DNA studies, this fern now is known as Telmatoblechum serrulatum. Telmato means marsh in Greek, and blechnum is said to refer to a type of fern (again in Greek). Now, swamp fern (Telmatoblechum serrulatum) only plant in this genus in Florida.
You will find this fern growing on the edges of marshes and in the dappled shade of hammocks. It is the most common terrestrial fern at the CBCP & the ORCA.
This fern is odd-pinnate. An uneven number of leaflets are attached Its central rachis (“spine”), leaving one leaflet at the “end”. This character is not uncommon and does not provide a definite ID.