The diagnostic characters which separate Hypochaeris glabra from H. radicata are more distinct than generally is assumed. In this study, a few new diagnostic characters are presented based on observations of plants in horticulture. In England, hybridisation between Hypochaeris glabra and H. radicata has been observed. Hitherto the hybrid between these two species has not been observed in the Low Countries, but its undetected presence may be the reason for the uncharacteristic large size of the flowering head that is given for Hypochaeris glabra in recent Dutch and Belgian Floras. The circumscription of the habitat of H. glabra also needs correction. The species certainly is not calcifuge, because it grows on calcareous soil as well.