Humulus lupulus, the common hop or hops, is a species of flowering plant in the hemp family Cannabinaceae, native to Europe, western Asia and North America. It is a perennial, herbaceous climbing plant which sends up new shoots in early spring and dies back to a cold-hardy rhizome in autumn. It is dioecious (having separate male and female plants). As the female cone-shaped flowers (hops) are used to preserve and flavor beer, the species is widely cultivated for the brewing industry. Description Humulus lupulus is a perennial herbaceous plant up to tall, living up to 20 years. It has simple leaves with 3–5 deep lobes that can be opposite or alternate. The species is triggered by the longer summer days to flower, usually around July or August in the Northern Hemisphere. The plant is dioecious, with male and female flowers on separate plants. The fragrant flowers are wind-pollinated. The staminate (male) flowers do not have petals, while the pistillate (female) flowers have petals enveloping the fruit. The female flower cones (or strobili) are known as hops. The fruit is an achene, meaning that it is dry and does not split open at maturity. The achene is surrounded by tepals and lupulin-secreting glands are concentrated on the fruit. The species is sometimes described as a bine rather than a vine because it has stiff downward facing hairs that provide stability and allow it to climb. Chemistry H. lupulus contains myrcene, humulene, xanthohumol, myrcenol, linalool, tannins, and resin. Hops are unique for containing secondary metabolites, flavonoids, oils, and polyphenols that impact the flavor of the products they are common in, such as beer. The bitter flavors in hops can be accounted for by acids composed of prenylated polyketides (a group of secondary metabolites), which highly impact the taste of hop-based products. Multiple genes have been identified as factors in the expression of taste including O-methyltransferase 1, geranyl diphosphate synthase, and chalcone synthase. Genomic analyses have shown evidence that the intervention of humans in the selection process of the hop over the thousands of years it has been cultivated have provided noticeable enhancements in aroma and bitterness as well as selection of varieties with high yield rates. Flowering, growth, and stress response Predicted genes in homologous primary contigs have been identified as accounting for various traits expressed via variation in the growth, flowering, and stress responses in the plant. These homologous primary contigs