Cannabaceae

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. Cannabaceae is of the rose order (Rosales). Members of the family are erect or climbing plants with petalless flowers and dry, one-seeded fruits. Hemp (Cannabis) and hop (Humulus) are the only economically important 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). Members of this family can be trees (e.g. Celtis), erect herbs (e.g. Cannabis), or twining herbs (e.g. Humulus). Leaves are often more or less palmately lobed or palmately compound and always bear stipules. Cystoliths are always present and some members of this family possess laticifers. Cannabaceae are often dioecious (distinct male and female plants). The flowers are actinomorphic (radially symmetrical) and not showy, as these plants are pollinated by the wind. As an adaptation to this kind of pollination, the calyx is short and there is no corolla. Flowers are grouped to form cymes. In the dioecious plants the masculine inflorescences are long and look like panicles, while the feminine are shorter and bear fewer flowers. The pistil is made of two connate carpels, the usually superior ovary is unilocular; there is no fixed number of stamens. The fruit can be an achene or a drupe.