Lemons may have originated as a two-step hybrid, the first arising in the area of northwest India and Pakistan, the second in the Middle East. Lemons arrived in the Mediterranean around 100 CE, were planted in orchards in Moorish Spain by 400, and are now mainly cultivated in subtropical regions. They’re valued for their acidity, often 5% of the juice, and their fresh, bright aroma, which is the base for many popular fresh and bottled drinks. There are many varieties of true lemon, and also a couple of further hybrids. The large, coarse Ponderosa variety is probably a lemon-citron cross, and the Meyer lemon, a thin-skinned, less acid version brought to California in the early 20th century, is probably a cross between the lemon and either orange or mandarin, with a distinctive flavor due in part to a thyme note (from thymol). Lemons are generally “cured” for better shelf life; they’re picked green and held in controlled conditions for several weeks, where their skin yellows, thins, and develops a waxy surface, and the juice vesicles enlarge.