Technical Abstract: The resins produced by either lupulin or leaf glands of more than 41 genotypes of botanical varieties of Humulus lupulus L. collected from the wild in 9 mid-western and western American states were analyzed for the presence of prenylated flavonoids. A dichotomous distribution, i.e., the presence or absence, of 4'-O-methylchalcones in wild, American-collected hops was confirmed. Xanthogalenol and other 4'-O-methylchalcones were ubiquitous in H. lupulus var. lupuloides E. Small and in H. l. var. pubescens E. Small. Both of these botanical varieties are distributed in mid-western North America, east of the Rocky Mountain divide, in the Missouri-Mississippi River basin. Presence of the 4'-O-methylchalcones was inconsistent between specimens of H. lupulus var. neomexicanus Nelson and Cockerell. This species is primarily distributed in western states but also extends across the divide to the Missouri-Mississippi River drainage. Most of the H. l. var. neomexicanus collected east of the divide contained 4'-O-methylchalcones as did H. l. var. lupuloides and H. l. var. pubescens, while most specimens of H. l. var. neomexicanus from west of the divide did not. In a few localities, such as the Kaibab Plateau, Arizona, and Phantom Canyon, Colorado, genotypes of H. l. var. neomexicanus containing 4'-O-methylchalcones and those without, were sympatric. Further morphological and molecular evaluations of this wild collected germplasm are in process.