59 
1920-21.] Interruption of Endodennis. 
Fig. 6. Endodermis complete, and beginning of external cambium. x 250. 
Fig. 7. Endodermis complete, and formation of secondary tissue from external 
cambium, x 250. 
Fig. 8. Endodermis curved and continuity broken by pressure of tissues within. 
Cells Xj x 2 show the beginning of separation of endodermal cells. x 250. 
Fig. 9. Three endodermal cells are shown pushed out from the ring. The bundle 
just within was formed from internal cambium ; tissues to right and left from 
external cambium. x 250. 
Fig. 10. Endodermal cells pushed right out to cortex by the activity of internal 
cambium. Those cells on right have been left behind among secondary elements. 
x 200. 
Fig. 11. Separation of endodermis by intrusion of cortex. x 250. 
Photographs. 
I. Curving and splitting of endodermis ( x ) due to inside pressure. x 24. 
II. Endodermal cells (x) pushed out to cortex by internal cambial activity, x 24. 
{Issued separately March 17 , 1921 .) 
