The genus of heath is 'ERICA', which is a group of over 800 species of flowering plants in the family Ericaceae. These plants are native to many parts of the world, including Europe, Africa, and Asia. They are often found in moorland and heathland habitats, and they are known for their small, bell-shaped flowers. The genus ERICA is also known for its evergreen shrubs, which are popular in landscaping and gardening.