Specimens collected from the forest areas of Mazandaran Province (Iran), Kojour, between Lashkenareh

and Gandis-Kala village showed significant characteristics. At first glance, these specimens looked similar to A. szowitsianum, but with no indumentum on fruit. Further studies showed that those specimens belong to a new species, Alyssum mazandaranicum Mirzadeh & Assadi sp. nov., which was confined to the ecotone area between Euro-Siberian and Irano -Turanian regions. More populations of this new species were also found in other localities with similar ecological circumstances. Here, the new species is described, illustrated and compared with the closest taxon.