Flowers with petals not fused into distinct tube. Leaves mostly in basal rosette but stem leaves opposite, with pungent aroma when crushed, the margins markedly serrate. Inflorescences cylindric, subtended by whorled bracts. Leaves not in basal rosette, without pungent aroma when crushed, the margins not markedly serrate. Inflorescences not cylindric nor subtended by whorled bracts.
Leaf blades cordate.
Leaf blades not cordate. Placentation not free-central. Leaf blades with arcuate secondary veins and characteristic ladder-like tertiary veins between the secondary veins. Leaf blades without above venation. Leaves often heteromorphic, one leaf of node much larger than other.