OF LOWER GR KENS AND PLANTS. 107 



@rowth-roig* to the number of 19 are present, well marked, 

 variable in thickness up to a maximum of 3 mm. in the outer 

 zones, containing about 135 cells. The spring wood forms only 

 about one-fourth of the whole thickness of the ring, and its cells 

 are slightly crushed and filled with black carbon grains, which 

 give the rings their well-marked appearance. The autumn 

 wood-elements are not very much thickened. 



The primary wood is well preserved, projecting in large 

 numbers of bundles into the pith (PI. VI). Resin-canals are 

 present in the primary bundles (Pis. VI & VII, fig. 1). 



The secondary wood is close in texture, the elements small, 

 slightly rounded at the corners, adjacent cells on slightly alter- 

 nating tangents, so that the rounded walls fit compactly. In 

 the first three annual rings the medullary rays are numerous 

 and conspicuous, but in the later-formed wood they are narrow 

 and remarkably inconspicuous. Horizontal and vertical resin- 

 canals are present throughout all the wood, but are more 

 numerous in the first five, than in the outer rings. 



Uniseriate medullary rays are numerous and conspicuous in the 

 earlier rings of wood, while in the outer rings the cells are small 

 and very inconspicuous in transverse section ; one to fifteen cells 

 high, principally 1-6. In radial section the complexity of the 

 ray, the abietinean pitting of the walls, and the ray-tracheids 

 are well seen. Multiseriate rays contain resin-canals. 



DKTAILS OF ELEMENTS. ThejMfA-cells are large (PI. VI, p., & 

 PI. VII, p.), about 90 p. in diameter, rounded in outline, and 

 with walls considerably thickened and pitted. This is shown 

 in PI. VII, p., where the pits between adjacent cells are very 

 clearly seen in the photograph. A number of the cells contain 

 blackened and granular contents, but none seem specialised as 

 resin- cells, nor are there any special thick- walled idioblasts. 

 In longitudinal section the cells are elongated to a length about 

 equal to 1J to 2 transverse diameters. The cross-walls are 

 mainly rectangular. 



The primary bundles in the wood vary somewhat in size ; an 

 average bundle is shown in PI. VII, fig. 1. Round the pith 

 there are not less than 30 bundles, with smaller ones between 

 them. The proloxylems appear to be endarch (PI. VII, 

 fig. 1, px.), but it is not possible absolutely to confirm this 

 from the sections available, as none of the longitudinal sections 



