Sept. mo.] FUJI!.— SOME REMARKS ON THE CRET. FLORA ETC. 205 



the centrifugal xylem is maintained to be an important point 

 for the determination of a centripetal wood (Bernard, 1904.). 

 In the case of the present pine leaves, the outermost empty cell 

 of each radiating rjow of cells, i. e. the cell next to the inner- 

 most ray cell with contents, is the cell which leads the entire 

 centripetally arranged elements. But this cell does not show 

 the appearance of the ordinary initials of a centripetal xylem. 

 At any rate, the above described structure does not represent 

 any part of a mesarch structure, although it may have at 

 most to do with a kind of centripetal wood. 



As the structures ventral to the centrifugal xylem are so 

 strikingly similar in P. densiflora, P. Thunbergii, and Prepinus 

 statenensis, so far as the figures of the latter plant show 

 (Jeffrey, on Cretaceous Pine leaves, 1908. Annals of Botany, 

 Vol. XXII. PI. XIII. figs. 14, 15. &c), the above considera- 

 tions seem to be equally applicable to the case of the centripetal 

 wood of Prepinus statenensis. A closer examination of the figures 

 11, 14, and 15 of Prepinus statenensis (Jeffrey, I.e.) shows that 

 the radiating rows of the centripetal xylem, here more than 10, 

 instead of 2 or 5, are the direct continuations of the ray plates 

 unmistakably ; thus they are morphologically in the same planes 

 with the corresponding ray cells, and alternate with the proto- 

 xylem groups of the centrifugal xylem. The protoxylem groups 

 in the above mentioned figures 11, 14, and 15 of Prepinus 

 statenensis are chiefly represented by the elongated gaps left 

 by the breaking down of the elements of this portion, as it is 

 usual with them in most plants and often in above mentioned 

 two species of pines. That is why here the elements of the 

 centripetal wood are, unlike the usual type, so regulary arranged 

 with intervals. So it appears to me that Pinus densiflora, P. 

 Thunhergii, and Prepinus statenensis are not essentially different 

 as far as the arrangement of tissues ventral to. the centrifugal 

 xylem is concerned. 



Here I may add in passing that some years ago I have 

 observed in the stem of Pinus Thunhergii a kind of centripetal 

 elements, and have reported in 1908 as a case of existence of 

 centripetal elements in the usual vegetative axis of a modern 



