Maidenhair Ferns

Adiantum spp. (2 in Missouri)

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Photo of a northern maidenhair fern
Maidenhair ferns are distinctive and beautiful. This is the northern maidenhair fern, Adiantum pedatum, which is found statewide.
Family

Pteridaceae (maidenhair ferns)

Description

Missouri’s native maidenhair ferns (genus Adiantum) are perennials that spread with short-creeping rhizomes. Each frond is divided once or twice, and the leaflets (pinnules) are generally wedge-shaped or rectangular, with lobed outer tips. The leaflet veins are easy to see, and they divide by twos one to several times, forming a fan pattern. Spores are produced on the undersides of bent-under edges of the leaflet lobes and are hidden by the bent-under edges. Spores are produced June–August. The leaves are deciduous (they drop off in winter or during dry conditions).

Missouri has two species of maidenhair ferns:

  • Northern maidenhair fern (A. pedatum var. pedatum) is common statewide and is one of the most widespread ferns in Missouri. Its leaves are erect, with each leafstalk (petiole) branching into two arching stalks (rachises) at the tip, with each of these bearing additional stalks (the featherlike pinnae) attached along the upper (inner) side of each stalk (rachis); the pinnae bear the short-stalked leaflets (pinnules). In spring, the fiddleheads are pink.
  • Southern maidenhair fern, or Venus hair fern (A. capillus-veneris), is scattered mostly in the Ozarks. Its fronds droop, and the leafstalks (petioles) don’t branch at the tips. Instead, the leafstalk is straight or somewhat bending as the leaflets branch off of it.
Key Identifiers

 

The dichotomous branching of leaflet veins is distinctive: each vein branches into two veins, which each branch again into two, and so on.

Size

Frond length: 12–30 inches (northern maidenhair fern); 5–30 inches (southern maidenhair fern).

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Photo of a southern maidenhair fern, closeup of pinnule showing branching veins
Southern Maidenhair Fern Leaflet
In maidenhair ferns, the leaflet veins branch into twos, which then branch into twos, and so on. This is southern maidenhair fern, which grows mostly in the Ozarks.

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Photo of southern maidenhair fern showing drooping habit
Southern Maidenhair Fern
Southern maidenhair fern (Adiantum capillus-veneris) has fronds that droop, and its leafstalks (petioles) don’t branch at the tips.

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Photo of northern maidenhair fern showing distinctive growth habit
Northern Maidenhair Fern
Northern maidenhair fern looks a little bit like miniature palm trees. The growth habit helps separate Missouri's two maidenhair fern species.

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Photo of a colony of northern maidenhair ferns
Northern Maidenhair Fern
Northern maidenhair fern (A. pedatum) has an erect main stalk that divides at its top into 2 arching branches, which branch further along the inner side of each.

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Photo of lush cascades of southern maidenhair fern on the side of a bluff
Southern Maidenhair Fern
Dense colonies of southern maidenhair fern cascade down bluffs along many Ozark spring-fed streams and rivers.

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Photo of southern maidenhair fern plants growing on a bluff in Howell County
Southern Maidenhair Fern On Bluff
Lush, cascading southern maidenhair fern greets canoeists as they float bluff-lined Ozark streams.

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Photo of a developing northern maidenhair fern crosier
Northern Maidenhair Fern Fiddlehead
The developing fronds (fiddleheads, or crosiers) of northern maidenhair fern are pink. This photo was taken April 20, 2013, at Clifty Creek CA.
Habitat and conservation

Both Missouri species of maidenhair ferns usually occur in moist, rich, cool locations. Southern maidenhair fern commonly grows on moist ledges and crevices of dolomite bluffs and boulders along streams, rivers, and spring branches. It can grow in dense colonies on bluffs along many Ozark spring-fed streams and rivers. Northern maidenhair fern is less common on rocks or boulders; instead, it is more often found on rich slopes of ravines in mesic (moist) upland forests.

Distribution in Missouri

Northern maidenhair fern is scattered statewide. Southern maidenhair fern is mostly found in the Ozark and Ozark Border regions.

Life cycle

Ferns have a two-parted life cycle. The portion of the cycle we usually notice represents the sporophyte generation, since it produces spores (not eggs or sperm). Each spore can germinate and become a plant representing the other half of the cycle, the gametophyte. People rarely notice the gametophyte-generation plants, which are tiny, green, flat, heart- or kidney-shaped leaflike structures. The gametophytes produce gametes (eggs and sperm), which must unite to create a new sporophyte plant. Water is needed in order for the sperm to swim to the eggs.

Human connections

Several species of maidenhair ferns are cultivated as ornamentals indoors and outdoors. Their delicate feathery or lacy leaves with shiny dark stems makes them popular.

The genus name, Adiantum, has Greek roots and means “unwetted”: water rolls off the leaflets.

Maidenhair ferns have had a variety of medicinal uses by cultures worldwide, and some people still use it.

Ecosystem connections

Plants that grow in wet places help to hold the soil in place during rains and floods.

Certain aphids, mealy bugs, an other small insects apparently suck the juices of maidenhair leaves, but mammals and other vertebrates generally do not eat it. Some maidenhair ferns are labeled “deer-resistant” since deer will not eat the foliage.

Unlike mosses and algae, ferns and fern allies have a vascular system for carrying nutrients and water throughout their roots, stems, and leaves. But unlike flowering plants, they do not have flowers, fruits, or seeds.

In case you’re wondering, the ginkgo tree (Ginkgo biloba) is sometimes called “maidenhair tree” because of its fan-shaped leaves with dichotomous venation — but ginkgos, which produce seeds and no spores, are not ferns at all.