Description: A specimen of this native perennial fern consists of a much-branched bipinnate leaf and its petiole. This compound leaf is 6-24" across and nearly as long; it is reniform (kidney-shaped) or fan-shaped in outline, and held more or less horizontal to the ground. The petiole is 6-18" tall; it is black or dark brown, wiry, and erect. The petiole divides into two major branches that widely diverge from each other. Along one side of each branch, there are several straight leafy stalks (pinnae) that are odd-pinnate. Each leafy stalk (rachis) is up to 12" long and 2" across; it has 4-24 pairs of leaflets along its length and a single terminal leaflet.
These leaflets are arranged alternately
along the stalk on short petiolules; they are medium green. The non-terminal
leaflets are up to ½" long and 1" across; they are plume-shaped. One
side of the non-terminal leaflet is smooth and slightly curved, while the other
side is shallowly cleft and crenate-dentate. The larger lobes of each leaflet
have rounded or truncate tips. The terminal leaflets are up to ¾" long
and ¾" across; they are fan-shaped. The lower two sides of the terminal
leaflet are smooth and straight, while the upper side is shallowly cleft and
crenate-dentate. The sporangia (spore-bearing structures) are located near the
lobed tips of the leaflets. Each of these leaflet tips folds downward and
partially covers its sporangia; these small sporangia are arranged together in
a narrow band. The spores are produced and released during the summer or fall.
The root system is fibrous and rhizomatous. Small colonies of plants are often
produced from the long slender rhizomes.
Cultivation:
The preference is light shade, moist to mesic conditions, and a loose fertile
loam with an abundance of humus and decaying leaves. This fern likes high
humidity and it should be located in a shaded area that is protected from the
wind.
Range & Habitat:
Maidenhair Fern is occasional to locally common throughout Illinois; it has
been found in every county of the state. Habitats include rich deciduous
woodlands, rocky wooded slopes, and shaded ravines where limestone or sandstone
is close to the ground surface. Although it is fairly common, this fern is not
normally found in degraded woodlands where the original ground flora has been
largely destroyed.
Faunal
Associations: Very little information is available about
floral-faunal relationships for this fern. It has been reported that
White-Tailed Deer don't browse on its fronds, which may be an indication of
their toxicity.
Photographic
Location: Along the wooded slope of a sandstone ravine at Shades
State Park in west-central Indiana. The photographed plant is still
immature.
Comments: This is one of
the more distinctive and beautiful ferns in the state. Its closest relative is
Adiantum capillus-veneris (Venus Hair Fern), which is located in areas
south of Illinois. The central stalk (main rachis) of this latter species is
branched on both sides; these side stalks are quite short and have only a few
leaflets each. These fan-shaped leaflets are more narrow than those of the
Maidenhair Fern. Sometimes Adiantum pedatum is referred to as the
Northern Maidenhair Fern, while Adiantum capillus-veneris is referred to
as the Southern Maidenhair Fern.