188 DESCRIPTIVE CATALOGUE 



of the autumn wood are rather thicker than in the spring 

 wood, and the tangential pits can be very clearly seen even in 

 transverse section. Resin-canals, both normal and traumatic, 

 are absent. Resin- containing ccylem-parenchyma cells are 

 exceedingly numerous and conspicuous in the wood (PI. XVI, 

 figs. 1 & 2, r.p.). 



The medullary rays are also numerous and fairly conspicuous ; 

 they are all uniscriatc, 2-8 tracheids distant in the greater part 

 of the wood, but as much as 14 or so tracheids distant in some 

 parts of the outer rings. The cells appear all alike, and in 

 tangential section the rays are low, principally 2-3, and up to 

 5-6 cells high. The cainbium is normal, an<l is partly preserved 

 between the phloem and xylem (PI. XVI, fig. 2, c.). The phloem 

 is very much crushed, but appears to be quite normal (PI. XVI, 

 fig. 2, ph.). Mingled with the soft cells are thickened stone- 

 cells. The cortorisvery partially preserved, but shows numbers 

 of large resin-canals throughout those portions which are present 

 (PI. XVI, fig. 2, r.r.). 



DETAILS OP ELEMENTS. The pith consists of roundish cellf, 

 varying up to 40-50 p. in diameter. They fit into each other 

 without leaving much intercellular space, and their walls arc 

 slightly thickened and pitted (PI. XVI, fig. 1, p.). In longi- 

 tudinal section the elements are not much elongated, and an; 

 chiefly squarish in outline. Owing to obscurities in the petri- 

 faction 1 cannot feel certain whether or not stone-cells are 

 present. 



The primary wood forms irregular small bundles of what 

 appears to be entirely centrifugal wood. In radial section 

 the protoxylems can be seen, and a few of them seem to 

 have scalariform and spiral elements ; but most of them arc 

 covered by very minute roundish pits (PI. XVII, fig. 2, ^>..r.), 

 in which a strand of protoxylem lies in the centre of the 

 field, and to the right are the small secondary tracheids 

 with their larger round-bordered pits. Leaf-trace strands of 

 these small-pitted elements pass out in the medullary rays. 

 The secondary tracheids vary somewhat ; the largest of them 

 measure up to 25 p in diameter, but most of them are 

 considerably less than this. In the inner zones of the 

 wood they are much rounded at the corners, and in the outer 

 zones they are squarer and more regular, as can be seen by an 



