A botanical tour in the southern parts of Tirap Frontier Division lying to the south-east of the Margherita-Nampong-Pangsupass line and bordering upon Burma and Manipur, undertaken over a period of 20 days during August-September, 1958, pelded 518 species of angiosperms and 120 species of pteridophytes amongst others. This paper presents the geology, topography, soil and vegetation together with a comprehensive analysis of the floristic composition of the vegetational types and is followed by enumeration of the species of angiosperms in the Appendix.
Analysis of the species collected and belonging to angiosperms established the following ten families as the richest ones on the basis of the number of species. Orchidaceae (50), Rubiaceae (29), Gramineae (28), Urticaceae (27), Leguminosae (21), Compositae (19), Cyperaceae (19) and Gesneraceae (17), Verbenaceae (12), Labiatae (12). These together represent about 45% of the species collected. About 68 species not recorded by Kanjilal et al(1934-1940) have been reported as additions to the dicotyledonous flora of Assam and NEFA. Several are reported here as new records of species for India.