462 NOTES ON IIYDROCOTYLE AMERICANA. 



FlG. 14. Transversal cut of a stem, Ep., epidermis. B., Lark. D., the duct out- 

 side the phloeme. P., pith. 



15. Transversal cut of a stolon. Ep., epidermis. 13., bark. D., the duct. P., 

 the pith. 



1G. Transversal cut of an old tuber. Ep., epidermis. B., bark t Eud., endoj 

 dermis. D., the duct. Ph., phloeme. X., xylem. P., pith. 



IT A duct, D., of an old tuber. 



