Engler's Versuch einer Entwickelungsgeschichte der Pflanzenwelt (Leipzig, 1879-1882), we should have in Siberia (a) the arctic region; (b) the sub-arctic or coniferous region - north Siberian province; (c) the Central-Asian domain - Altai and Daurian mountainous regions; and (d) the east Chinese, intruding into the basin of the Amur.