The Scrophulariaceae used to be a diverse group of plants with irregular flowers. Most of the members of the group have recently been reorganized into the Orobanchaceae and the Plantaginaceae, leaving the Scrophulariaceae a much smaller family than before. The petals of the Scrophulariaceae are united into a tube. The plants that remain in this family have anther sacs that have "anther sacs usually confluent and opening by a single distal slit oriented at right angles to the filament or +/- U-shaped." ("Plant Systematics, A Phylogenetic Approach" by Judd, Campbell et al, page 484)