Pliocene to early Pleistocene. By events of intercontinental dispersals, they reached southern Africa twice and North America at least three times. Two tetraploid lineages expanded rapidly, with the ability to colonize lower belts of the salt marshes than their diploid relatives. Inbreeding and geographical isolation led to a large number of reproductive isolated species that are only weakly differentiated. The taxonomic classification of this genus is extremely difficult (with one paper calling it a "taxonomic nightmare"). The determination of species seems almost impossible for non-specialists. The reasons for these difficulties are the reduced habit with weak morphological differentiation and high phenotypic variability. As the succulent plants lose their characteristics while drying, herbarium specimens often cannot be determined with certainty and are less suited for taxonomic studies. Molecular phylogenetic studies have regularly revised the circumscription of the genus. It was considered distinct from Sarcocornia in 2007 and 2012 studies. A 2017 study resulted in Sarcocornia being sunk into Salicornia, substantially increasing the size of the genus, which was divided into four subgenera. Species , Plants of the World Online accepted the following species: Salicornia alpini Lag. Salicornia ambigua Michx. Salicornia andina Phil. Salicornia bigelovii Torr. Salicornia blackiana Ulbr. Salicornia brachiata Roxb. Salicornia capensis (Moss) Piirainen & G.Kadereit Salicornia crassispica G.L.Chu Salicornia cuscoensis Gutte & G.K.Müll. ex Freitag, M.Á.Alonso & M.B.Crespo Salicornia decumbens (Toelken) Piirainen & G.Kadereit Salicornia decussata (S.Steffen, Mucina & G.Kadereit) Piirainen & G.Kadereit Salicornia disarticulata Moss Salicornia dunensis (Moss ex Adamson) Piirainen & G.Kadereit Salicornia erectispica G.L.Chu Salicornia europaea L. Salicornia fruticosa (L.) L. Salicornia globosa (Paul G.Wilson) Piirainen & G.Kadereit Salicornia helmutii Piirainen & G.Kadereit Salicornia hispanica (Fuente, Rufo & Sánchez Mata) Piirainen & G.Kadereit Salicornia lagascae (Fuente, Rufo & Sánchez Mata) Piirainen & G.Kadereit Salicornia littorea (Moss) Piirainen & G.Kadereit Salicornia magellanica Phil. Salicornia maritima S.L.Wolff & Jefferies Salicornia × marshallii (Lambinon & Vanderp.) Stace Salicornia meyeriana Moss Salicornia mossambicensis (Brenan) Piirainen & G.Kadereit Salicornia mossiana (Toelken) Piirainen & G.Kadereit Salicornia natalensis Bunge ex Ung.-Sternb. Salicornia neei Lag. Salicornia nitens P.W.Ball & Tutin Salicornia obclavata (Yaprak) Piirainen & G.Kadereit Salicornia obscura P.W.Ball & Tutin Salicornia pachystachya Bunge ex Ung.-Sternb. Salicornia pacifica Standl. Salicornia perennans Willd. Salicornia perennis Mill. Salicornia perrieri A.Chev. Salicornia persica Akhani Salicornia perspolitana Akhani Salicornia praecox A.Chev. Salicornia procumbens Sm. Salicornia pruinosa (Fuente, Rufo & Sánchez Mata) Piirainen & G.Kadereit Salicornia pulvinata R.E.Fr. Salicornia quinqueflora Bunge ex Ung.-Sternb. Salicornia rubra A.Nelson Salicornia senegalensis A.Chev.