 Bremekamp, in 1965, presented a classification of Acanthaceae that differed from that of Lindau, for his Acanthaceae excluded genera that lack retinaculate fruits.He placed Nelsonioideae within Scrophulariaceae, classified Thunbergiaceae and Mendonciaceae as distinct families and divided his Acanthaceae into two groups (Acanthoideae and Ruelloideae) based on the presence or absence of cystoliths, articulate stems, monothecate anthers, and colpate pollen.In Scotland and Vollesen's 2000 study, they accepted 221 genera and detailed five major groups within Acanthaceae s.s. (that is, those possessing retinaculate fruits), which is equivalent to Acanthoideae Link sensu Lindau 1895.