MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



8l 



TO, and i6 cm. in length respectively, and only the larger one devel- 

 oped lateral branches of noticeable size, but all had a cluster of 

 foliar rudiments at the extremities of the pinnae. 



A spore-bearing pinna usu- 

 ally arises from the stipe near the 

 point where it branches, but in 

 the etiolated cultures this organ 

 was represented by an atrophied 

 structure near the base of the 

 stipe. The stipe was much longer 

 than the normal, and the exces- 

 sive growth was seen to take place 

 in the upper part of the main stalk 

 and in the adjacent bases of the 

 branches. The diameter of the 

 stipe was something greater than 

 that of the normal organ. 



The upper portion of the stipe 

 has two schizosteles of crescentic 

 cross-section with the concavities 

 facing each other in the normal, 

 and distinctly separated by masses 

 of fundamental parenchyma. 

 The etiolated stipe had two large 

 schizosteles almost confluent at 

 the margins in much the same 

 manner as the structures in the 

 basal portion of the normal main 

 stipe. 



The thickening of the normal 

 epidermis is noticeably lacking 

 in the etiolated stipe. The paren- 

 chymatous cells are slightly 

 larger and with thinner walls in 

 the etiolated specimens. The sclerenchymatous tissue shows but 

 little thickening in the etiolated stipes, and a similar lack of devel- 

 opment is to be seen in the xylem, in which the walls are hardly 

 half the diameter of the normal. 



Stomata, which are open when examined in water, are present 



Fig. 37. Etiolated culture of Botrychium 

 obliqimm. 



