Adiantum pedatum. Maidenhair Fern.
This is a beautiful native fern of the upper midwest. The fine, lacy green foliage sits elegantly above the ground a foot or so, making it a great plant to pair with a lower groundcover such as wild ginger. This fern can be found in it's native habitats in rich, deciduous forests and woodlands. Historically, this fern was used medicinally by Native Americans.
A shade loving perennial, this fern prefers a moist, well drained soil. The preferred soil pH is 4.6 - 6.6, although I have seen it pop up in the cracks of limestone walls.
This is an excellent shade garden plant, planted en masse or singly. Add compost to the soil, and keep it humus rich by letting leaf debris collect.