Noun | 1. | ![]() plant genus - a genus of plants family Hamamelidaceae, Hamamelidaceae, witch-hazel family - comprises genera Hamamelis, Corylopsis, Fothergilla, Liquidambar, Parrotia, and other small genera witch hazel, witch hazel plant, wych hazel, wych hazel plant - any of several shrubs or trees of the genus Hamamelis; bark yields an astringent lotion |