A genus of 66 accepted species of mostly deciduous, occasionally evergreen, shrubs in the Hydrangeaceae family native to North and central America, Asia and parts of southeastern Europe. They have simple, often toothed opposite leaves and 4-petalled white bowl-shaped flowers that superficially resemble citrus flowers, and some with a scent reminiscent of oranges, hence their common name, mock-orange. The scented species in particular have been extensively cultivated as park and garden plants and there are many cultivars and hybrids bred for flower form and size.