High Quality Content by WIKIPEDIA articles! Wahlenbergia is a genus of between 150-270 species of flowering plants in the family Campanulaceae, with a cosmopolitan distribution except for North America; the highest species diversity is in Africa and Australasia. Wahlenbergia species have dispersed widely, even to oceanic islands, and there are four species known from the island of St Helena, including the now extinct species W. roxburghii.