Striga asiatica (Scrophulariaceae) is an obligate root hemiparasite of mainly C-4 grasses (including cereals). It is the most widespread of the 42 Striga species occurring in many semi-tropical, semi-arid regions of mainly the Old World. Examination of herbaria specimens revealed that S. asiatica has a wider geographical distribution, is present at higher altitudes and occurs in a more diverse range of habitats than previously reported. The host range is also larger than previously reported and is likely to include a large number of C-3 plants. Morphology of examined specimens revealed variation in size and corolla colour suggesting the existence of ecotypes. Climate may exert a significant influence on the distribution of S. asiatica given the diversity of potential host plants and their distribution beyond the current recorded range of S. asiatica
