MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



133 



sible to determine which of these tissues was lacking. The meta- 

 xylem was but little different from the normal. The walls of the 



Fig. 89. Etiolated culture of Osmunda cinnatnomea. 



protoxylem (consisting of groups of small cells immediately inside of 

 the xylem) were not so much thickened as in the normal. The in- 



