The main online key contains information on roughly 250 species of ferns that occur in lowland Amazonia. It is a multi-entry key, so the questions about the plant do not need to be answered in order. Just pick the questions that you find easy to answer and ignore the rest. All species are illustrated, so you can take a shortcut and check the photos of any species at any stage.
A separate key is provided for the genus Triplophyllum. More single-genus keys will be added in the future.