The paper deals with the names of plants, constituent units of compound geographic names attested in the territory of the urban district of Khulun-Buir (New Barga Eastern khoshuu, New Barga Western khoshuu, and Old Barga khoshuu) which is situated in the north-eastern part of the Autonomous Region Inner Mongolia of the People's Republic of China. The analysis of phytonyms internal form leads the author to conclude that visual perception of the plants plays the leading role in the process of their naming. In this logic, feather grass and sedge received their names due to the sticking-out and long stalks, willow was entitled due to a curly crown, and pea sluub - for its sharp spines. The local hydrographic term uyet 'piece of water' is revealed. It originated by metaphorical transfer from the plant name uyet 'saltmarsh-grass'. The Bargut orographic term qur gamma alj 'defiladed hollow' is a homonym of the plant named quryalj `low love grass' but these happen to go back to different etymons: the orographical term is connected with the verb *qur gamma- 'to disappear, hide' while the phytonym derives from a figurative root *qur gamma 'something long, extended'. It is revealed that phytonyms (as the main component of compound geographical names) generally designate a forest or an underbrush. Only the word khailaas 'elm' is used to define a separate tree. Such trees are believed to have their own spirits or masters, and therefore, as a rule, serve as objects of honoring described in multiple legends of Bargut folklore. The study of phytonyms can provide information on the dynamics of Mongolian peoples' migration and settlement at the northeast of China, the way they transformed the geological system and formed the picture of the physically and spiritually reclaimed space.