THE STEM OF CALAMITES 



27 



side by side in different parts of one and the same 

 specimen. 



The following considerations serve to identify the 

 leaf-traces. We constantly find in all specimens of 

 Catamites, that at every joint a whorl of small and 



m.r> 



m.p 



Fig. 8. — Ca/amites communis. Tangential section of wood, passing through a node, 

 and cut near the pith. v.b., Vascular bundles of the stem. /./., leaf-traces cut 

 transversely as they turn outward at the node. Note that they are only half as 

 numerous as the bundles of the stem, m.r., primary medullary rays, i.e., small- 

 celled tissue of the rays below the node, corresponding to Williamson's " infranodal 

 canals." x 12. S. Coll. 897. (G. T. G.) 



uniform bundles passes out, and though it is only in 

 the very rarest cases that we are able to trace out 

 these bundles continuously into the leaf, yet there is 

 no doubt that these outgoing bundles are really the leaf- 

 traces. For one thing, their arrangement precisely 

 corresponds with the arrangement of the leaves, as 



