48 STUDIES IN FOSSIL BOTANY 



canals were left behind intact. 1 In this exceptionally 

 beautiful case, these radiating spokes correspond in size, 

 shape, and position to the dilated infranodal rays, shown 

 in so many of the specimens with structure. We know, 

 from the evidence of the medullary casts with branches, 

 that the prints in question occurred below the nodes 

 (see Figs. 2 and 3) : it follows that the dilated rays, or 

 " infranodal canals," when present, were also below the 

 node, and this fact is often of value in determining the 

 top and bottom of a specimen in doubtful cases (cf. 

 Figs. 8 and 9). 



1 This specimen is figured by Williamson in Part ix. of his memoirs 

 "On the Organisation of the Fossil Plants of the Coal-measures," Phil. 

 Trans. 1878, Part ii. Plate xxi. Fig. 31. 



