The ashes (Fraxinus) have been divided into several distinct sections, which are nicely laid out in this paper: https://www.researchgate.net/publication/225262277_Systematics_of_Fraxinus_Oleaceae_and_evolution_of_dioecy
Can/should we create these taxa on iNat? iNat includes sections for Carex and (soon) Salix. I would find it helpful since some sections (e.g. Melioides, which contains green, white and pumpkin ash) include species which are difficult to distinguish but clearly distinct from other ashes.