Manchester Memoirs, Vol. li. (1907), No. 13. 5 



Williamson's view that this division of the pith cells 

 involved an increase in dimensions of the primary wood 

 (Will., '83, '95) seems to be physically impossible (Solms- 

 Laubach, '91, p. 229), and not to be in accord with the 

 fact that the shape of the dividing cells is not materially 

 altered. 



In longitudinal section the pith is seen to consist of 

 elongated parenchymatous cells, arranged in vertical rows. 



These cells are separated by horizontal walls, but 

 secondary oblique walls also occur. 



The average dimensions of a pith cell are 'lyx'oSx 

 •08 mm. 



An interesting character of the pith is the occasional 

 occurrence in it of apparently isolated tracheids. 



This character suggests comparison with L. vasculare, 

 Binney ( = L. selaginoides, Sternb. ? Carr., Will.). 



(2) Wood. 



In a branch (A 144), with a " Halonial" tubercle, the 

 greatest diameter of which is 17 mm., the diameter of the 

 wood is 2 - 25 mm., so that the wood is small in amount 

 {Fig. 1, Plate I). 



In this specimen the average thickness of the ring of 

 wood is just over 1 mm. 



The wood presents an unusually even contour, con- 

 trasting strongly with that of L. Harcourtii (Witham). 



It consists of a ring (3 or 4 tracheids broad) of 

 tracheids, of fairly uniform diameter, about -13 mm., which, 

 when followed outwards, rapidly gives place to a very 

 narrow but continuous belt of much smaller tracheids, 

 about '04 mm. in diameter. 



This belt is only 1 or 2 tracheids wide. 



The protoxylem points consist of small groups of 

 tracheids, about 6 to a group, which seldom project more 

 than 2 tracheids, 



