OF LOWER GREENLAND PLANTS. 



231 



very excessively thickened walls. The pits on the radial walls 

 of the tracheids are almost all in one row, a few only are in 

 irregular pairs. These pits may lie very close together, or 

 separated by as much as 2-3 times the width of their own 

 borders. The diameter of the border of the pit is nearly as great 

 as fche traeheid-wall in which it lies (text-fig. 66). Wood- 

 parenchyma containing resin is very sparsely scattered through 



/ /r />,/ 

 // t *'/ * 



O 





X 



X 





\ 



Text-fig. 66. Podocarpoxylon Gothani, sp. nov. Radial section showing 

 the tracheids, t., with their round-bordered pits, and the medullary ray- 

 colls, m., with single large oval pits per tracheid-field. No. V. 131946. 



the wood. A few elements in the radial sections show the 

 transverse walls, which slightly constrict the lumen. 



The tangential diameter of the cells of the medullary rays in 

 transverse section may be equal to the adjacent tracheids, but 

 in most cases is rather less. In radial extension a ray-cell 

 seems to correspond to about 5 or tracheids, but not very many 



