Plenasium angustifolium
Plenasium angustifolium is a fern in the family Osmundaceae. The genus Plenasium is recognized in the Pteridophyte Phylogeny Group classification of 2016 ; however, some sources place all Plenasium species in a more broadly defined Osmunda, treating this species as Osmunda angustifolia. It is native to eastern Thailand, Laos and southern China, and has been introduced into India and Sri Lanka.