New record and range expansion of Mesosphaerum suaveolens (L.) Kuntze (Lamiaceae) in Southern Zimbabwe

In the present study, we report a new distribution range of Mesosphaerum suaveolens (L.) Kuntze in Southern Zimbabwe, commonly known as bush mint or pignut, is native to tropical America and has now been recorded as a naturalized and invasive species in Zimbabwe. This new record is based on field identification of species populations growing in the wild, diagnosis and verification of the species identity using herbarium specimens and a thorough literature review. A detailed species description and dichotomous key are provided to distinguish M. suaveolens from a closely related M. pectinatum (L.) Kuntze. Both species are rapidly spreading in Zimbabwe due to high environmental adaptability and reproductive capacity, enabling the species to thrive in a wide range of habitats in the country. The findings of this study call for the need to monitor the invasion of M. suaveolens in the country as the species poses a major threat to biodiversity, ecosystem health and bio-resources.