284 



Mr Arber, Notes on the Binney Collection 



sist of irregular rows of cells, and are distinctly broader than 

 in many specimens. The external layer is almost entirely absent. 

 The structure, as a whole, is typical of Lyginodendron Old- 

 hamium (Binney), but the preservation is not of the best. 



Slide 180. Text-figure II. 



This section was probably cut less than an inch, i.e. less than 

 the length of an internode below section 179. The structure is 

 essentially similar to that of the former slide, but is interesting 

 as showing a leaf-trace passing through the secondary wood. 



Figure II. Lyginodendron Oldhamium (Binney). Transverse section of the stem, 

 showing a leaf-trace passing up through the trace-gap in the .secondary wood, 

 x 40. Photo, by Tams, Cambridge. 



This trace, which is shown considerably enlarged in figure II, 

 seems to have had some difficulty in forcing its way up through 

 the trace-gap, owing to the pressure of the secondary wood. It 

 has left a portion of its own secondary wood behind it on each 



