IN CEYLON. 29 



In some specimens of D. montana from Trincomalee I 

 observed that some oblique bands of wood parenchyma were 

 connected at the outer end to the median cells of a tangential 

 band of parenchyma, and within, to a medullary ray at a 

 point opposite to another tangential line of parenchyma. 

 By this means tangential bands of one zone can be con- 

 nected, almost directly, with a band in an older zone, along 

 a different radius. Such an arrangement must greatly 

 facilitate the transference of food materials through the 

 parenchymatous system. 



The tangential and oblique bands of wood parenchyma 

 therefore effect an excellent communication with all 

 elements, excepting perhaps the vessels and tracheids. The 

 remaining part of the wood parenchyma is, however, specially 

 associated with these elements. In most of our species the 

 large vessels are surrounded or flanked on their tangential 

 surfaces with relatively wide lumined but short wood- 

 parenchyma cells. These are in communication with the 

 other cells of wood parenchyma or medullary rays, and 

 therefore a complete communication is effected with every 

 element of the secondary xylem. 



The vertical distribution of these elements is easy to 

 follow since they are arranged one above another through 

 a considerable vertical distance. They form very long 

 columns of cells, often as many as twelve cells in the same 

 row. The majority form single straight lines with the 

 components exactly above one another ; frequently one cell 

 abuts on to another, not end to end, but by the radial 

 walls, thus giving the terraced system in the vertical 

 direction. 



There is nothing unusual in the form of these elements. 

 In transverse outline they may be any shape from circular 

 to crudely four-sided, but only rarely do they exhibit sharp 

 corners. They are elongated considerably in the vertical 

 direction, the vertical walls being straight and the end walls 

 flat or occasionally tapering at one end when in contact 



