118 



DESCRIPTIVE CATALOGUE 



lie round the resin-tracheids, and form in some cases interrupted 

 tangential bands between them (text-fig. 28). The vertical 

 extension of these cells is about 2-4 times their transverse 

 diameter, which equals that of the adjacent tracheids. Many 

 of the wood-elements contain blackened contents, a few of 

 these which lie isolated among the empty Iracheids may possibly 



Text -fig. 28. Pityoxylon Wovdwardi, sp. nov. Transverse section of part 

 of autumn wood with resin-canals, e., epithelium of canal; p., paren- 

 chyma; .., limit of autumn wood ; s. } spring wood ; m., medullary raj'. 

 No. V. J54290. 



have been resin-containing tracheids. There is nothing, how- 

 ever, to distinguish them from the others, and the great majority 

 of the elements with blackened contents are clearly due to 

 mineralisation. 



