Seventy-five populations corresponding to 12 taxa (species or subspecies) that include Odontites (9 taxa), Odontitella (1 taxon) and Macrosyringion (1 taxon) from the Iberian Peninsula, and Bartsiella (1 taxon) from Morocco have been studied. For the first time, a chromosome number is reported for the genus Bartsiella, monospecific and endemic to Morocco, B. rameauana (2n = 24), and Odontites kaliformis (2n = 22), O. viscosus subsp. asturicus (2n = 24) and O. viscosus subsp. granatensis (n = 11), endemic to the Iberian Peninsula. A new chromosome number is vreported for Macrosyringion longiflorum (2n = 22), Odontitella virgata (n = 12), O. viscosus subsp. australis (2n = 20, 22, 24) and O. recordonii (2n = 26). All the studied taxa were diploid (2x). In the case of O. vernus s.l., a tetraploid level (4x) was also found. This species in its wider sense includes O. vernus s.str. and O. vulgaris, which is often considered an independent species. Out of the forty-six populations of O. vernus s.l. studied, thirty were found to be tetraploid (2n = 4x = 40, O. vernus for many authors) and sixteen to be diploid (2n = 2x = 20, O. vulgaris for many authors).
