Notes on the samphires (Salicornioideae, Chenopodiaceae–Amaranthaceae) in Madagascar and Europa Island, with further conclusions on their chorology in Africa

The last treatment of Chenopodiaceae in Madagascar was published in 1954 and since then, the generic circumscription of Chenopodiaceae including Salicornioideae has changed drastically. The Madagascan Salicornioideae (samphires) are still insufficiently studied. Salicornia pachystachya described from Madagascar had a turbulent nomenclatural and morphological history, frequently considered as Arthrocnemum pachystachyum due to the alleged similarity of the seed characters with other Arthrocnemum species, or considered in a broader sense including the related Salicornia perrieri. However, the reproductive features of S. pachystachya confirm its placement within Salicornia, and the thick inflorescences and longer seeds distinguish it from S. perrieri, another native Madagascan species. Two other members of Salicornioideae in Madagascar are the subshrubby Salicornia mossambicensis, erroneously named S. fruticosa or Arthrocnemum natalense, and Tecticornia indica. Herein, a diagnostic key is provided for the delimitation of four samphire species in Madagascar, and the lectotypes of Salicornia pachystachya and S. perrieri are designated. Only two species, S. pachystachya and Tecticornia indica, are recorded for Europa Island, and their habitat preferences in this location are presented, as well as a discussion of the species composition and chorology of samphires in continental Africa.