Seedling Structure of Gymnosperms . IV. 321 
meristem is bounded on its inner side by a number of short tracheides 
having an appearance which strongly recalls that usually associated with 
Diagram i. Ephedra .—In this and the following text-figures, the protoxylem is represented 
by black areas, the metaxylem by dots, the phloem by diagonal shading, and the transfusion elements 
by cross hatching. 
many transfusion tracheides of the cotyledons of other Gymnosperms. 
These elements, in Ephedra , form a bridge connecting the xylem-masses 
of the two corresponding bundles. 
Y 
