VIl] 



MEDULLATION 



125 



Fig. 1 18. i-iv. Transverse sections, in succession from below, of the axis of a young plant of Anemia 

 phyllitidis. i, protostele gives off leaf-trace without any interruption of the endodermis; ii, proto- 

 stele higher up ; iii, still higher, with central pith ; iv, same stele giving off a leaf-trace without 

 interruption of the endodermis ; note isolated tracheide in the pith. 



V, vi. Transverse sections of adult stele of Schizaea riipestris. vi, shows continuous xylem round 

 central pith; v, shows departure of a leaf-trace: to the left a root-trace. Endodermis is dotted. 

 (X150.) 



Fig. 119. A, B. Transverse sections of the young stem oi Botrychitim Lunaria, showing medulla- 

 tion, the departure of the leaf-trace, and the first steps of cambial activity. Note isolated tracheides 

 in the pith of A, and the complete endodermal investment of ^. ( x 125.) 



