230 Double Cross-Grain 



cells with brown, resinous looking contents. The walls of the elongated 

 cells were thickly sprinkled with numerous fine pits. 



In Xylia dolabriformis a layer, one or two cells deep, with darker 

 contents, and apparently fibrous, bounded the rings. 



The structural definitions of the rings in Gmelina arborea was much 

 less distinct than in the other species although the rings themselves were 

 apparent to the eye. An indistinct layer of parenchyma appeared to 

 delineate the rings. 



With regard to the relation between seasonal changes and the periods 

 of growth of these trees, the following information was obtained from 

 Brandis(3): 



Chloroxylon Swietenia. Common in the deciduous forests of the 



Western Peninsula. Flowers March to April. Leaves renewed in 



May. 

 Shorea robusta. Never quite leafless. The young foliage appears in 



March with the flowers. 



Hardwickia binata. 



Xylia dolabriformis. Flowers while leafless, in March and April. 

 Gmelina. arborea. Leaves shed from February to April. New foliage 



appears in May. Flowers from February to April, generally before 



the leaves are out. 

 Calophyllum sp. (Poon). Evergreen forests. 



Similar seasonal changes are also recorded for the greater number of 

 the remaining species. 



The similarity, with regard to the structure of the rings and to the 

 response to seasonal changes, between the Indian trees and the trees 

 of temperate climate indicates that the rings shown in the Indian timbers 

 are of the nature of growth-rings correlated with seasonal changes and 

 lends support to their use as indices of contemporaneity. 



Detailed Investigation. 



The object of the method adopted was to find the inclination of the 

 grain in every growth-ring of the trunk and to study how the inclination 

 varied from ring to ring. 



With the material to hand it was only possible to do this for one 

 transverse and one radial plane of the drum, nevertheless, the data 

 obtained were sufficient for forming a clear idea of the changes which 

 the course of the grain underwent during the growth of the tree. 



The rings were counted on the transverse disc of each species ex- 



