Microgonium

Ahamada H. Saïd, Sabine Hennequin, Germinal Rouhan & Jean-Yves Dubuisson, 2017, Disentangling the diversity and taxonomy of Hymenophyllaceae (Hymenophyllales, Polypodiidae) in the Comoros, European Journal of Taxonomy 313, pp. 1-53 : 16

Subgenus Microgonium

Subgenus Microgonium is represented by four species. All Comorian species have glabrous lamina margins, submarginal false veins and sori more or less immerged in the laminae with tubular base and lips more or less developed, sometimes dilated as a collar but never bilabiate, and with undifferentiated margins. The widespread D. cuspidatum was cited for the archipelago in literature ( Roux 2009) but represented in collection by only four specimens. This contradicts its supposed abundance in the region, as well observed in Mascarenes (pers. obs.; Grangaud 2010). In addition the species is usually distributed from sea level up to 1350–1400 m, and more frequently below 1000 m. All the supposedly Comorian specimens (including recent collects firstly identified as D. cuspidatum ) were collected at high elevations, above 1000 m. A precise investigation of these specimens reveals in fact that they are not D. cuspidatum but rather the distinct D. erosum (Willd.) J.P.Roux. Didymoglossum cuspidatum would be absent in Comoros but confusion with D. erosum as detailed here-after remains easy. This explains why we, however, chose to maintain D. cuspidatum in the Xper database, in order to allow its potential identification in future collects.