Solving the riddle of Aspidium ameristoneuron Fée, a misunderstood Cuban or Mexican species of Ctenitis (Dryopteridaceae) – Occasional Papers from the Herbarium Greuter, 7

The holotype of <i>Aspidium ameristoneuron</i>, the correct application of which has long been in doubt, has been identified in the herbarium RB in Rio de Janeiro. It was found to have been mislabeled, and its true origin is Mexico, not Cuba as stated in the protologue. The history of the labeling error is reconstructed, and the identity of <i>Aspidium ameristoneuron</i> with the species so far known as <i>Ctenitis salvinii</i> (here renamed <i>Ctenitis ameristoneuros</i> <b>comb. nov.</b>) is demonstrated. The names and synonyms involved are typified.