The young ferns:

In late August 2017, I received an email that the most appropriate name of this fern should be Diplazium proliferum according to the information from the Catalogue of Life website (updated in August 2017) since Athyrium accedens was listed as a synonym of Diplazium proliferum. In Singapore, this fern was discovered by Joseph Lai in June 2010 [1-2]. In the footnote of his blog, he indicated that "we have now 11 species of Athyrium in Singapore". Since the 2009 Singapore Flora Checklist did not list any Athyrium species, he seemed to imply that the 10 Diplazium species listed in there should indeed be Athyrium species. A later publication in 2013 on leaf-cutting propagation of the fern [2] did not offer any clarification on this topic. The Ferns of Thailand website used Diplazium accedens as the accepted name and Athyrium accedens as a synonym. Diplazium accedens was also listed as a synonym of Athyrium accedens in the Catalogue of Life website.

Further search led me to a book published in 2004, titled "Plant Resources of Tropical Africa 2: Vegetables" where Athyrium accedens was indicated as a synonym of Diplazium proliferum (page 288). However, the Plant List website indicated Athyrium accedens as an accepted name. As the correct accepted name remained unclear to me, I will leave the name as it is for the time being until more concrete evidence is reported.

Reference:

[1] Lai J. Athyrium accedens: New botanical record for Singapore. Nature Watch 2010;18:20-21. | Read article |

[2] Yeo CK, Tan SY, Koh CY, Chong KY, Ng XY, Lai JTK. Leaflet-cutting propagation of Athyrium accedens (Blume) Milde (Woodsiaceae). Nature in Singapore 2013;6:39-43. | Read article |