Air-dried (for 30 days) pooled leaves from 4th to 10th verticils (1.5 g) or flowers (0.5 g) from each examined plant were hydro- distilled as previously described (Mun ̃oz-Bertomeu et al., 2006). Also, fresh leaves (0.1g) from each of the five developmental stages previously indicated were transferred to 20-mL glass tubes containing 4mL hexane with n-tetradecane and naphthalene as internal standards. Small glass beads (0.1 g; 425–600 mm in diameter, Sigma) were incorporated into the mixture before shaking up in a vortex for 1min. After 4h incubation at room temperature, the extract was filtered through Millipore mem- branes (0.22mm) and concentrated under a nitrogen stream to 1 mL. Essential oil quantification was performed by GC and GC/MS analyses as described in Mun ̃oz-Bertomeu et al. (2006).