Throwback Thelpyteris Thursday: Southern Shield Fern

Southern shield fern and widespread maiden fern are the names favored by Dr. Richard Wunderlin, the University of South Florida botanist responsible for the Florida Plant Atlas, for the fern pictured above, Thelpteris kunthii. Other common names abound, including Kunth’s maiden fern, river fern, throat fern, normal shield fern, and stately maiden fern. Its species name, kunthii, honors Carl Sigismund Kuth, a German botanist (1788 – 1850).

In 2014, Bob Stolze provided this description …

Widespread shield fern (Thelypteris kunthii)

This species of Thelypteris has fronds that are quite hairy on both sides, widest at the base, rather thin in texture, and are usually a light, yellow-green. Unlike the other two species along the trail, the basal veins run freely to the edge of the segment, and do not merge with opposing ones.

Habitat: Common in Florida in rocky woods and edges of cypress swamps. Southeastern United States, West Indies, and Central America.

This somewhat tropical fern grows in moist woods throughout the southeastern U.S., and its range is limited by its lack of cold tolerance. In 2014, Diane LaRue (Class of 2012) sent the following 2 photos from the Oslo Riverfront Conservation Area (ORCA) hammock loop trail …

Its pinnately compound fronds are a lime to light green and about 2 1/2 – 3′ long. Like other Thelypteris ferns, southern shield fern grows in clumps from a rhizome (underground plant stem). Note, per the description from Bob Stolze, the deeply lobed leaflets (pinnae), how the pinnae taper to a point (acute apex), and the hairy midrib.

The “spores”, technically called sori (clusters of sporangia, structures that produce & protect spores), often have a “C” shape and are located along the center of the pinnae along the mid vein.

Selby Botanical Gardens describes southern shield fern as “one of the best ferns for the home landscape in Florida. Beautiful yet manageable, southern shield fern performs in a variety of conditions, from moist to dry soil, from shaded areas of the garden to full sun.” Enjoy seeing this striking fern at ORCA and consider including it in your home landscape.