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.
Habitat and Conservation
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.
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.