The results are reported of a survey made in 1982-83 along the hilly uninhabited forest tract between the villages of Koilabas and Jamunibas in the Siwalik Ranges of the central Himalayas. The forest type is dense natural tropical broadleaved and has been heavily exploited by the local inhabitants. Some 166 species were identified and are listed, including 56 tree species of which Pinus roxburghii (occurring up to 915 m alt.) was the only conifer. There were only a few (18) shrub species in the area, 17 herbaceous and grass species, 16 climbers and 2 semi-parasitic angiosperms. There were differences in floristic composition with alt. and on N.- and S.-facing slopes; these are described and discussed.