sept. 1910.] FTJJTI.—SOME REMARKS ON THE CRET. FLORA ETC. 203 



moment that these plants became fossilized, we will have 

 nearly the same structure as that of the Cretacous pine allies, 

 as far as the broad large celled zone of transfusion tissue is con- 

 cerned. The cell walls of all tissues within the endodermis, the 

 latter included, are lignified, with exceptions of the phloem, the 

 elements of protoxylem, and the parenchyma accompanying 

 resin canals, in case any resin canals are present. 



On the ventral side of the xylem we find thin-walled, 

 lignified, vertically elongated elements. They fill up the space 

 between the xylem and the transfusion zone. This tissue on the 

 ventral side of the xylem sends out a branch and wedges between 

 the two vascular bundles, and may reach the phloem portions. 

 In the outer limit of the phloem portion, a transverse row of one 

 or two layers of sclerenchymatous fibres are developed. They 

 may be continuous or interrupted. They are often present in 

 the outer limit of the above mentioned tissue on the ventral 

 side of xylem too ; also I have once observed them developed in 

 the wedge portion between the two xylem portions. Among 

 this tissue ventral to the xylem, we see usually two rows of 

 cells in P. densiflora and some five rows of cells in P. Thun- 

 bergii radiating, often quite regularly, from each xylem portion 

 and extending to the sclerenchymatous fibres above mentioned 

 or to the transfusion tissue. These cells are thin walled, ligni- 

 fied, and vertically much elongated. These structures inside the 

 endodermis seem particular neither to these two species of 

 Pinus, nor to the genus Pinus. 



Now when we compare the above described structure of Pinus 

 densiflora and P. Thunbergii with that of Prepinus, we see, in 

 the development of the endodermis and the infolding of cell walls 

 of the assimilating tissue of these two living species, a consider- 

 able progress in the evolution of tissues ; other than these 

 differences, the tissues of the present pine leaves seem to corres- 

 pond in the main to those of the leaves of Prepinus statenensis 

 and of Prepinus japonicus. The great development of broad 

 transfusion zone in Prepinus is quite comparable to that of P. 

 densiflora or of P. Thunbergii ; the inner narrower zone of trans- 

 fusion sheath described by Jeffrey may be compared either 



