With a view to study the vegetation and flora of the tarai forests and grasslands of the Bahraich district of Uttar Pradesh, bordering upon the tracts of forests in the Nepalese territory, three seasonal tours undertaken in this forest division in March and November, 1964 by the Senior author (G. Panigrahi) and in February, 1965 by O. P. Misra, yielded 530 species of Angiosperms and 14 species of Pteridophytes as represented by 1076 field numbers of plants. (Wherever the name of the Collector is not given between the locality and the field no. in the enumeration appended to this paper, "PANIGRAHI" may be cited).
The paper presents an outline of the three classes of forest types viz. Sal, Miscellaneous and Grass and an analysis of the floristic composition in the Katarniaghat-Dharmanpur-Motipur-Doba-Chakia-Chardha and Bhinga forests which are isolated blocks separated by 8-16 km by intervening tracts of cultivation and grazing grounds, except the forests of Dhramanpur and Motipur, which adjoin.
The Sal forests are divided into Moist (Gangetic) High level alluvial, dry (Gangetic) alluvial, moist (Gangetic) low level alluvial, dry (Gangetic) alluvial subtypes; the Miscellaneous forests are subdivided into North-Indian Moist Teminalia, Cane brakes, tropical valley fresh water swamp, Khair-babul, Khair-sissoo, North dry-mixed deciduous, Aegle and Gangetic saline scrub; the Grasslands belonging to the lower alluvial moist savannah type and extending over about 37,000 acres, represent the largest of the forest sub-types, discussed below.
It has been established that the richness of the grass in the savannah, is not due to the large of different species in the area, but due to the distribution of some species over more stable riverain flats, which are subject to occasional floods and are locally known as PHANTAS.