Taxonomic Status of Diploid Southern Hemisphere Brackens (Pteridium: Dennstaedtiaceae)

Abstract

Diploid bracken ferns separate morphologically, genetically and reproductively into a predominantly northern hemisphere clade comprising 11 subspecies placed in Pteridium aquilinum (L.) Kuhn and a predominantly southern hemisphere Austral/South American clade of two taxa. Circumscription of Pteridium esculentum (G.Forst.) Cockayne is here emended to include both taxa of the southern clade, respectively P. esculentum subsp. esculentum from Australasia and P. esculentum subsp. arachnoideum (Kaulf.) J.A.Thomson comb. nov. from Central and South America.