Manchester Memoirs, Vol. Ivii. (1913), iV^. 18. 9 



generally regarded as a member of the Taxodineae, but 

 has also beeii considered as possibly Araucarian. 



The T}'lodendron remains from Prince Edward Island 

 in Canada, examined by Miss Holden,* differ from the one 

 described in this communication in the possession of a 

 discoid pith being similar to that of the Cordaitales, but the 

 detailed structure of the wood is of Araucarian type, so 

 that Miss Holden leaves their affinities undetermined. 

 She considers them not closely related to the Cordaitales, 

 and there seems to her " to be no sufficient grounds for 

 relating them to any group of living conifers." 



The specimen described in the present communication 

 differs in the structure of its pith, both from the Tj'lo- 

 dendron described by Isotonic and from the Canadian 

 forms, by the possession of numerous secretory passages. 

 The presence of these canals, resembling so closely those 

 of many of the members of the Cycadales, inclined me at 

 first to the view that this silicified inner portion of the 

 stem might have belonged to a member of that group. 

 On the other hand the structure of the secondary wood is 

 not Cycadian in nature but more of the Araucarian type, 

 the pits being in one or two rows, and not occupying the 

 whole width of the tracheid, a point on which Gothan 

 lays some stress.^ 



A reconciliation between the C}'cadian or Cordai- 

 talean nature of the pith and the Araucarian nature of 

 the wood is now possible, since Thompson has described 

 mucilage ducts in the medulla of the cone of Araiicaria 

 imhricata}^ 



- loco. cit. 



'■' Gothan, W. " Uber die WandUingen der Iloftiipfelung bei den 

 Gymnospennen im Laufe der Geologischen Epochen." Silzungsberichte, 

 der Ges. natiirf. Freuude. Berlin, 1907. 



^" Thompson, R, B. "On the Comparative Anatomy and Affinitiej of 

 the Araucarineae." Phil. Trans, Series B., vol. 204, 1913. 



