Mairis’s maidenhair (A. x mairisii), is a rare hybrid, is sterile and thought to be a cross between the Southern maidenhair (A. capillus-veneris) and an unknown species (perhaps the tender A. cuneatum). Surprisingly, this chance hybrid is vigorous, easily grown and more cold tolerant than either of its suspected parents. It produces lacy, bright green fronds supported by brittle charcoal-black stems. It holds its fronds well into the fall season although it is deciduous. Brought to market by Casa Flora’s research team who were able to coax the plant to reproduce through tissue culture making it widely available for the first time.