“…Such differences among the essential oils could be due to the density of oil glands associated with the plant tissues, changes in the growth environment as the plant develops, and/or a shifting distribution of carbohydrates to plant growth and development as opposed to essential oil synthesis. For example, several plants alter essential oil production to attract pollinators and inhibit pests and herbivores (Patricelli et al, ; Hosni, Msaada, Taârit, & Marzouk, ; Figueiredo, Barroso, Pedro, & Scheffer, ). Earlier studies (Crocoll, Asbach, Novak, Gershenzon, & Degenhardt, ; Werker, Putievsky, & Ravid, ; Giuliani, Maggi, Papa, Maleci Bini, ) indicated that the glandular trichomes and percentage of essential oil in oregano are primarily concentrated in the flowers.…”