The paper describes the fibre length and ray height of the five tree species, namely Calophyllum polyanthum Wall., Garcinia cowa Roxb., G. xanthochymus Hook., Kayea floribimda Wall, and Mesua ferrea Linn, of the family Guttiferae. In G. cozva and G. xanthochymusthe fibre length and ray height are higher and longer than those of the other species. These two microscopic features work as good characters in delimitating the species of Guttiferae. There is a progressive trend of increase of fibre length and ray height from near pith to sapwood for all the species