Cannabaceae is a small family of flowering plants. As now circumscribed, the family includes about 170 species grouped in about 11 genera, including Cannabis (hemp, marijuana), Humulus (hops) and Celtis (hackberries). Celtis is by far the largest genus, containing about 100 species. Other than a shared evolutionary origin, members of the family have few common characteristics; some are trees (e.g. Celtis), others are herbaceous plants (e.g. Cannabis).