Included here are relict Hyrcanian forests of the coastal plains extending in a crescent around the south and southwest of the Caspian Sea including the area around Lenkoran, Gilan and Mazanderan. It also extends up the northwestern slopes of the Talish Mountains and the northern slopes of the Elburz Mountains.
Of the endemic and near endemic vascular plants so far recorded there are 138 species in 83 genera and 41 families but no endemic genera. However, this area is a refuge for the near endemic genus Parrotia which is a surviving member of of the once widely distributed family Hamamelidaceae.
Browicz, K. 1987. Chorology of the Euxinian and Hyrcanian elements in the woody flora of Asia. Plant Systematics and Evolution, 162: 305-314.
Hedge, C. & Wendelbo, P. 1978. Patterns of distribution and endemism in Iran. Notes of the Royal Botanic Garden, Edinburgh, 36: 441-464.
Zohary, M. 1971. The Phytogeographical Foundations of the Middle East. In: Plant Life of South-West Asia. Eds. P. H. Davies, P. C. Harper & I. C. Hedge. The Botanical Society of Edinburgh.
Zohary, M. 1973. Geobotanical Foundations of the Middle East. Volumes 1 & 2. Gustav Fischer Verlag, Stuttgart & Swets & Zeitlinger, Amsterdam.Zohary, M., Heyn, C. C. & Heller, D. 1980. Conspectus Florae Orientalis. The Israel Academy of Science and Humanities. Jerusalem.