High Quality Content by WIKIPEDIA articles! Green Mountain maidenhair fern (Adiantum viridimontanum) is a rare fern limited to outcrops of serpentine rock in New England and Canada. A hybrid between Adiantum pedatum (northern maidenhair fern) and Adiantum aleuticum (western maidenhair fern), it closely resembles its parent species. In all three, the leaf blade is cut into finger-like segments, themselves once-divided, which are borne on the outer side of a curved, dark, glossy stalk (the rachis). The "fingers" may be drooping or erect, depending on whether the individual fern grows in shade or sunlight. Spores are borne under rolled flaps of tissue (false indusia) at the edge of the ultimate blade segments, a characteristic unique to the genus Adiantum. A. viridimontanum is difficult to distinguish from its parent species in the field. It can generally be separated from A. pedatum by the shape of the ultimate segments and by its habitat on thin, exposed serpentine soils rather than in rich woodlands. It more closely resembles A. aleuticum than A. pedatum; however, the stalks of the ultimate segments and the false indusia are longer, and the spores larger, in A. viridimontanum when compared to A. aleuticum.