NO. I GROWTH LAYERS IN TREE BRANCHES — CLOCK ET AL. 9I 



Fig. 31a. — Interrupted densewood (idw) formed by the insertion of extremely thin 

 densewood cells in the band of densewood thus interrupting the normal transition 

 outward. 



Fig. 31b. — Interrupted lightwood (ilw) formed by insertion of extra thin cells in the 



lightwood zone. 



