Knob weed (false ironwort)
Hyptis capitata

The hairy (i.e. pubescent) stems are four-angled (i.e. quadrangular) and usually develop pairs of branches in the upper leaf forks (i.e. axils).
The bright green leaves (5-15 cm long and 2-6 cm wide) are oppositely arranged and widely spaced along the stems. They are borne on stalks (i.e. petioles) 2-3 cm long and are egg-shaped in outline (i.e. ovate) or oblong in shape. The leaf blades have irregularly toothed (i.e. serrate) margins and pointed tips (i.e acute apices). Small oil glands are usually present on the undersides of the leaves.