PLATE I. 



Explanation of Letters Used. 



e — Epidermis. h — Hypoderm. 



r — Resin duct. tr — Tracheary tissue. 



I — Hypertrophied scales. 



2 — Secondary leaves. 

 Fig. I. Transverse section of normal or secondary leaf. (Sche- 

 matized). 



Fig. 2. Transverse section of hypertrophied scale. (Schematized). 

 Fig. 3. A shoot bearing both abnormal and normal leaves. 

 Figs. I and 2 are from camera lucida drawings. 



(54) 



