Adiantum aleuticum, the western maidenhair fern or Aleutian maidenhair, is a species of fern in the genus Adiantum. (Wikipedia)

Adiantum viridimontanum, commonly known as Green Mountain maidenhair fern, is a rare fern found only in outcrops of serpentine rock in New England and Eastern Canada. The leaf blade is cut into finger-like segments, themselves once-divided, which are borne on the outer side of a curved, dark, glossy rachis (the central stalk of the leaf). These finger-like segments are not individual leaves, but parts of a single compound leaf. The "fingers" may be drooping or erect,... (Wikipedia)