Practice question

Lamiaceae mint family distinguished vegetatively by quadrangular stem cross-section resulting from decussate growth and prominent collenchyma strands at corners providing mechanical rigidity, opposite decussate leaves often gland-dotted containing volatile essential oils like menthol thymol eugenol synthesized in peltate capitate trichomes. Floral traits include bilabiate zygomorphic corolla, didynamous four stamens two long two short, gynobasic style elevating ovary forming four nutlets mericarps. Apiaceae stems hollow furrowed bearing umbel, Rutaceae terete stems with oil glands but not square, Solanaceae alternate leaves lacking aromatic oils. Square stem therefore reliable field character visible without magnification.