Vegetative key to the families

STEMS SQUARE (or quadrangular), smooth or hairy but not scabrous; leaves opposite or rarely whorled, fragrant but usually without oil dots; fruit separating into 4 articles Lamiaceae
Calyx divided into 2 lips which may or may not be toothed
Perfect stamens 4
One or both calyx lips toothed or lobed
Upper calyx lip 3-toothed; lower lip 2-toothed Prunella
Upper calyx lip entire; lower lip acutely 4-toothed