Isoflavonoids in non-leguminous taxa: A rarity or a rule?

The number of known isoflavonoid-producers increases slowly but continously. Isoflavonoids have been found in not less than sixty families falling into four classes of multicellular plants. Biosynthetically advanced structural types of isoflavonoids (rotenoids, pterocarpans, etc.) were recorded in both classes and all subclasses of flowering plants.