1. Humulus lupulus Linnaeus, Sp. Pl. 2: 1028. 1753.
啤酒花 pi jiu hua
Plants perennial. Petiole usually shorter than leaf blade; leaf blade 3-5(-7)-lobed, sometimes simple, 4-11 × 4-8 cm, abaxially glabrous or with scattered soft pubescence but without rigid spinulose hairs on veins, adaxially with few or no cystolith hairs marginally when young, base cordate, margin coarsely serrate, apex acute. Female flowers 2 per bract at least in middle of inflorescence; bracts imbricated into a globose spike. Infructescences globose, 3-4 cm in diam.; bracts ovoid, 1.5-2 cm, dry, membranous, apex acute. Achenes flat, included in bracts. Fl. autumn.
Gansu, N Sichuan, Xinjiang [N Africa, N and NE Asia, Europe, E North America].
A number of different varieties is usually recognized (Small, Syst. Bot. 3: 37–76. 1978), with the populations in China represented by at least both H. lupulus var. lupulus, a predominantly European to C and SW Asian variety, and var. cordifolius (Miquel) Maximowicz, a predominantly Japanese variety. In addition, the populations in S Gansu and N Sichuan may possibly be another, distinct variety. Further study is needed to sort out the pattern of varietal occurrence in China, which is complicated by the introduction and escape of cultivated var. lupulus for commercial production of hops for beer.
This species is cultivated throughout China, especially in E Shandong (Qingdao) and Xinjiang. The flowers and infructescences are important ingredients for beer making. The female flowers and bracts are used medicinally.