Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species.

Here we describe 18 new species of the Marattialean genus Danaea: D. alba, D. ampla, D. antioquiana, D. elongata, D. kessleri and D. panamensis (all in D. subg. Danaea); D. dilatata and D. opaca (in D. subg. Arthrodanaea); and D. andina, D. cuspidopsis, D. erosa, D. nasua, D. peruviana, D. polypinna, D. pumila, D. robbinmoranii, D. ubatubensis, and D. velona (in D. subg. Holodanaea). We provide illustrations, maps of geographical distribution, and nomenclatural notes for the new species. We also lectotypify the name D. media and propose that its recent resurrection was a mistake: both D. media and D. elata are synonyms of D. nodosa, which is widespread in Central America and the Greater Antilles; we find that D. pterorachis is a valid name applicable to the Costa Rican material that has been referred to D. media. We consider D. sellowiana and D. nigrescens as distinct species and these names applicable to D. subg. Danaea material from the Brazilian Atlantic Forest and Amazonia, respectively, and we also lectotypify the name D. nigrescens here. We accept D. cuspidata and D. betancurii as species distinct from D. moritziana. Evolutionary relationships and an identification key for the 79 species we currently recognize in Danaea are published in a parallel paper (Keskiniva & al. 2024). Citation: Keskiniva V. & Tuomisto H. 2024: Danaea (Marattiaceae) keeps diversifying, part 1: eighteen new species. – Willdenowia 53: 173–228 Version of record first published online on 22 January 2024. [ABSTRACT FROM AUTHOR]