202 THE BOTANICAL MAGAZINE. [Voi.xxiv.No.284. 



rays ' or ray plates, the topographic distribution of the sclerized 

 elements and transfusion tissue within the endodermis, together 

 with the presence or absence and the situation of hairs (or serra- 

 tions) on the leaf will be some points determining the generic 

 and the specific differences. 



Another alternative is that the fossil Pinus in question had, 

 besides 'short-shoot/ ' long-shoot ' which had green leaves 

 resembling in their shape and structure the primordial leaves of 

 the present day pines, while such green leaves of the Cretaceous 

 pines have disappeared in the present day pines and have been 

 replaced by brown scaly leaves. In this respect it may be 

 recalled that it is well known that the present day pines have 

 a tendency to produce a certain kind of primordial leaves on the 

 ' long-shoot ' as the correlative effect of damage of the main 

 shoot. Naturally there is no reason why we can not take the 

 fossil leaf for such, unless they are found very abundantly. 

 After all, the fossil leaf of Pinus yezoensis in question seems not 

 to represent one from a monophyllous brachyblast, but a vegeta- 

 tive leaf of an axis of the nature of a 'long-shoot,' either 

 young or old. 



Although I differ in the interpretation of the unusual shape 

 and anatomical structures of this pine leaf, the discovery of 

 this Pinus by Stopes and Kershaw is nevertheless interesting. 



At this occasion I should like to describe some of my ob- 

 servations on the leaf structure of Pinus densiflora and P. 

 Thunhergii, as it seems to show certain features relating to 

 these of Prepinus. In these -species the endodermis as well as 

 the infolding of the cell walls of the assimilating tissue are well 

 developed. The vascular bundle is, as is the rule in the subsec- 

 tion Pinea, divided into two. Inside the endodermis and sur- 

 rounding the vascular bundles, we see a broad zone of trans- 

 fusion tissue. The latter has a tendency to be differentiated 

 into the outer thin walled and the inner thicker walled, smaller 

 lumined zones. The transfusion cells and the intervening paren- 

 chymatous cells are not always very easy to distinguish, and 

 in some sections, we even doubt whether there are any cells 

 other than transfusion cells in this region. If we imagine for a 



