Amaranthus tunetanus (Amaranthaceae), a new species from Tunisia and a diagnostic key to the North African taxa in subgen. Albersia

A new species of Amaranthus (Amaranthaceae), A. tunetanus sp. nov. from Monastir Governorate (central Tunisia) is described and illustrated. The new species is morphologically similar to A. crassipes, A. crispus, A. graecizans subsp. aschersonianus, and A. scleropoides from which it differs mainly by characters of synflorescences and flowers. Distribution in Tunisia, notes of its preferred habitat, phenology, and the IUCN status of conservation are also provided. A diagnostic key to the 14 taxa of subgen. Albersia occurring in North Africa is also presented.