The family Acanthaceae in Uganda was used to demonstrate the use of herbarium data in showing distribution patterns and diversity of plants and their representation in protected ares. The geographical distribution of the species was determined from Herbarium specimens at the Makerere Univeristy Herbarium, Kew Herbarium and the Natural History Museum, London. More than 2900 collections in a total of 251 species and 52 genera were examined. Species richness was highest in the areas around the Rwenzori Mountains, Budongo Forest and along the northern shores of Lake Victoria, especially around Mabira, Also important were areas around Mt. Elgon, Moroto and Kigezi highlands and the Albertine Rift area. Many species were highly localized with very few known records. The protected area system of Uganda captured many of the species but there were many others occurring outside the main protected areas.