Pityrogramma x mckenneyi W. H. Wagner

Endemic

Fool's gold fern

Name honors Michael P. McKenney, the discoverer of this fern and investigator of Hawaiian names for Hawaiian plants, who assisted in supplying the Hawaiian names used in this book.

Characteristics intermediate between those of parent species. Plants medium-sized, clustered, terrestrial. Blades shiny green on adaxial surface, covered with pale, whitish yellow powder on abaxial surface. Pinnae auricles on large pinnules mostly small and rounded.

The malformed spores of this vigorous fern suggest its sterile, hybrid nature; nevertheless, it still forms clones by means of vigorously spreading root proliferations. Usually more robust than either parent species, sometimes dramatically so with a distinct caudex.

The distribution of this recently recognized hybrid is not known. First noted in 1987 in the Ho'omaluhia Botanical Garden on O'ahu. It can be found in other disturbed habitats where both parents coexist, and it has been found on Tantalus on O'ahu at a site where P. austroamericana was collected previously but is now absent.

Pityrogramma austroamericana x P. calomelanos may be distinguished by characteristics intermediate between those of its parent species and by a pale, whitish yellow powder covering the entire undersurfaces of the pinnae.