Secretory and glandular trichomes (SGTs) are found on the surfaces of above ground plant tissues of approximately one third of all vascular plant species. Humans are familiar with these structures because they contain the essential oils that give cooking herbs their distinctive smell and taste. In addition to making foods taste better, these uni- and multi-cellular appendages are proposed to play a critical role in plant protection against various environmental stresses including herbivore attack, pathogen infection, extreme temperature, and excessive light.