Asplenium forisiense is a small evergreen fern, normally growing on siliceous rocks and almost restricted to the south-western part of Europe. In 1988 it was discovered on a concrete wall along the Eindhoven canal during an inventory of Potamogeton species by boat. Forty-one individuals of the fern appeared to thrive on sandy soil between two iron beams used for a provisonal restoration. The nearest former locality of A. forisiense was in Belgium, prov. of West-Brabant, Saint-Denis-lez-Mons, where it was recorded in 1858, but has not been found since.