Adiantum aeluticum, the “Western Maidenhair” is found in a wide distribution range through Western North America. Growing in crevices on steep slopes where shade is available. It is semi evergreen although has died back completely during the winter in the Biodiversity garden. It will reach 600mm in optimum conditions; here it manages 300mm at most.
Adiantum pedatum, a close relative is found predominately on the N. E. of America and into northern Asia. The specimen growing in the atrium of the John Hope Gateway was grown, collected from spores on a plant 600mm tall with a spread of 1.5m. This was by the side of a forest track beneath dense woodland.
Both species are delicate plants to grow, have rounded rigid black stems. Both are appreciated by pteridologists and make fine additions to a fern collection; the difference? Ask a botanist.