A re-evaluation of the Dryopteris fadenii (Pteropsida: Dryopteridaceae) complex, with the new species D. rodolfii

Summary Dryopteris fadenii from tropical Africa and species closely allied to it are studied using macro-and micromorphological characters. These highly variable species are morphologically very similar and has few obvious characters separating them. Micromorphological features, however, in particular indusium features, spore size and perispore sculpture, as well as stoma size and frequency, support D. fadenii and D. ruwenzoriensis as distinct species. The study shows that a third entity, here described as D. rodolfii J.P. Roux, sp. Nova, forms part of the complex. Dryopteris fadenii is diploid and based on spore and stoma size as well as stoma frequency, it is postulated that D. ruwenzoriensis is tetraploid and D. rodolfii perhaps octoploid.