The term bell-flower is a common name for the genus Campanula, which is a group of flowering plants in the family Campanulaceae. The genus includes over 500 species of annuals, biennials, and perennials, many of which are popular garden plants. The flowers are typically bell-shaped and come in a variety of colors, including white, blue, purple, and pink. The plants are native to temperate regions of the Northern Hemisphere, but some species have been introduced to other parts of the world.