Cleavers(Galium aparine) are herbaceous annual plants of the family Rubiaceae, which are native to North America and Eurasia.
Stickywilly is widely distributed in North America. It occurs in every U.S. state except Hawaii [153]. Stickywilly is present in parts of northern Mexico and in most Canadian provinces [90,165]. The nativity of stickywilly is debated. While most accept this species as native, some consider it nonnative [163,171]. Still others suggest that stickywilly is a native, but that subsequent introductions have occurred as well [90]. In a literature review, it is suggested stickywilly arrived in the fur of animals crossing the Bering Strait into North America [28]. While debate regarding the nativity of stickywilly continues, it is in all likelihood native and is considered native in most literature [25,44,58,143]. For more discussion on the nativity of stickywilly see [62,90].
A distributional map of stickywilly is accessible through Plants database.