Shield Fern family (Dryopteridaceae)
Description: This native perennial fern has deciduous leaves about 23½' long in loose tufts. The petioles are mostly light green or straw-colored, becoming more dark toward the base; they have chaffy scales that are light to dark brown. These scales are less than 1 cm. (1/3") in length for var. angustum, while for var. asplenioides they are greater than 1 cm. (1/3") in length. The hairless green blades are 1-3 times longer than their petioles and lanceolate-ovate in shape; they are widest below the middle and up to 10" across. Each leaf blade is bipinnate with 8 or more pairs of linear-lanceolate leaflets (not necessarily opposite from each other); the larger leaflets have 16 or more pairs of subleaflets. The subleaflets are oblong-lanceolate, pinnatifid (shallowly cleft), and sessile or short-stalked; their margins are slightly serrated and revolute (rolled downward). The veins of the subleaflets are pinnate.
The reproductive structures (sori & indusia) are located on the underside of the subleaflets. There are several pairs of sori/indusia on either side of the central vein of each subleaflet. Usually, the elongated sori (spore-bearing structures) are slightly to moderated curved (like a crescent moon or sickle); on rare occasions, they are either straight or strongly curved. The indusia (protective membranes) are the same shape as their sori; each indusium attaches to one side of its sorus. The brownish spores of the sori are usually released to the wind during the summer or early fall. The root system is fibrous and rhizomatous. Vegetative offsets are often formed from the rhizomes, creating small colonies of plants.
Cultivation: The preference is dappled sunlight to light shade, moist conditions, and a loose loamy soil that is slightly acidic. This fern likes high humidity and some protection from the wind. Problems with disease and pests are uncommon.
Range & Habitat: Lady Fern is occasional in most areas of Illinois; it is uncommon or absent in parts of south-central and east-central Illinois (see Distribution Map). This circumboreal species is widely distributed in North America and Eurasia. Across this range, several varieties of Lady Fern have been identified. In Illinois, Athyrium filix-femina angustum (Northern Lady Fern) is the most common variety throughout the state. In southern Illinois, Athyrium filix-femina asplenioides (Southern Lady Fern) has been found in a few counties. Habitats include moist to mesic woodlands, rocky ravines, shaded seeps, and edges of swamps. In Illinois, Lady Fern is typically found in deciduous woodlands (e.g., Maple-Basswood), although it is also found in coniferous woodlands in areas north of the state. Occasionally, this fern is cultivated in woodland gardens because of its ornamental foliage.
Faunal Associations: Very little is known about floral-faunal relationships for this fern. White-Tailed Deer occasionally browse on the leaves of this fern during the summer. Because this fern is fairly large in size and forms colonies, it can provide significant cover for wildlife in those few areas where it is locally common. Overall, the value of this fern to wildlife appears to be low.
Photographic Location: A woodland garden near Busey Woods in Urbana, Illinois.
Comments: The Lady Fern is an ornamental foliage plant that adapts readily to cultivation. Like Dryopteris felix-mas (Male Fern), the rhizomes of Lady Fern contain an oil that has been used to expel intestinal worms (particularly tapeworms). An overdose of this oil is toxic and potentially fatal to humans, however.
In many ways, the leaves of Lady Fern resemble those of several Dryopteris spp. (Wood Ferns), particularly Dryopteris carthusiana (Spinulose Wood Fern) and Dryopteris intermedia (Common Wood Fern). In addition to having similar leaf blades, the latter two ferns also have scaly petioles. The Lady Fern differs from these species as follows: 1) Its leaves are usually larger in size, 2) Its leaves are deciduous, while the leaves of the Dryopteris spp. are evergreen, and 3) Its spore-bearing structures are slender (whether straight or curved), while the spore-bearing structures of the latter ferns are round. For a more detailed description of the differences between the varieties Athyrium felix-femina angustum (Northern Lady Fern) and Athyrium felix-femina asplenioides (Southern Lady Fern), see The Illustrated Flora of Illinois: Ferns (1967/1999) by Robert Mohlenbrock, or the website of Efloras (www.efloras.org). Some authorities consider these two varieties to be separate species, in which case Northern Lady Fern is referred to as Athyrium angustum and Southern Lady Fern is referred to as Athyrium asplenioides.