if you google 'botany in a day' you will find a book by an american author who has highlighted the idea of family pattern identification characteristics.
I like his work because the keywords and characteristics of the main famillies can help us identify when out foraging. Moreover , as we already know certain families are safe to eat, ie the mustard / cabbage family, then when we come accross one, and positively i/d it as a mustard, then we know we can eat it without knowing excatly what plant it is. The same methodology can be used with the mint family.
Furthermore, certain chemicals can be predominant and typical of a plant family and help us to understand potential medicinal benefits. For example the large mainly aromatic mint family, displays various arrays of volatile substances known as monoterpenes. Becasue we know they are antiseptic, we know that one of any of them will display this activity to a lesser or greater degree and can employ them medicinally again without specifically knowing the individual species. An example here is thyme. There are three wild species in Britain as well as the cultvated Thymus vulgaris. They all will contain the monoterpene molecule thymol, though with differing concentrations. Knowing the medicinal effects of thymol as antiseptic and expectorant, it will be safe to utilise any of them in this way.