Dichotomous Key for Identification of some Assam Timbers

Variations in wood anatomical features were used in the preparation of dichotomous key for identification of 52 tree species of Assam. Variance ratio (F) test indicated that variations were significant among the species and non-significant for the replication for fiber length, fiber diameter, wall thickness and vessel element length and vessel element diameter. The dichotomous key for identification was prepared at species level on the basis of 178 wood anatomical qualitative and quantitative features. In the preparation of dichotomous key, wood anatomical features like presence/absence of included phloem, oil cells, silica vitreous, spiral thickening, radial canal, presence/absence and location of prismatic crystals, variation in axial parenchyma structure, vessel and ray frequency, ray height, specific gravity, etc. were found useful out of 178 features. Different species of same genera like Dillenia and Elaeocarpus were separated at species level on the basis of wood anatomical features. Two species of Dillenia namely D. aurea and D. parviflora outside from Assam state were also included in the study to separate important Indian species of the genus Dillenia at species level.