MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 247 



Stems than on normal plants. It is to be seen, therefore, that the con- 

 clusions of Schober that the reaction of these structures is correlated 

 with the habit of the member on which they are borne are not sus- 

 tained (see page 22). 



Development of Stomata on Etiolated Stems. — The develop- 

 ment of stomata was likewise subject to great variation among the 

 different species examined, and an intimate connection was found 

 between the degree of development of the leaf or stem, and the dif- 

 ferentiation and number of these organs. Stomata were present on the 

 stems of A^ios, Asparagus, Bozviea, Hydrastis, Lyshnachia, Menis- 

 ■per^mmi, Optoiiia and Phytolacca, but as no special record was 

 kept of this feature it is probable that they might be found on many 

 other etiolated stems. Furthermore, the simple fact of the occur- 

 rence of stomata on any etiolated stem is of importance only when 

 similar data have been obtained from normal stems, and this was 

 neglected in my observations. So far as a general inspection of the 

 results may be taken to be of value, stomata appeared to be most 

 numerous on etiolated stems capable of long duration and extended 

 development in darkness, although shoots that were capable of for- 

 mation of foliar expansions sometimes showed stems entirely lacking 

 these organs. It is notable that no stomata were found on the etio- 

 lated aerial stalks of Podophyllum, and that the stomata on the stems 

 of Viola rostrata failed to open. Only a small proportion of the entire 

 number of prestomatal elements passed into the final stage in Phyto- 

 lacca, and the stomata on the cylindrical etiolated shoots of Opuntia 

 were much reduced in size. 



Lenticels of Etiolated Stems. — Lenticels appeared to be more 

 numerous, especially on the basal portions of stems of etiolated seed- 

 lings of Acer, and AEsculus than on normal seedlings, and lenticellar 

 formations were also more abundant on the lower portions of the 

 etiolated stems of Ibcrvillea and Sniilax than in the normal. On 

 the other hand, lenticels normally present in Populus did not develop 

 beyond the first stage in etiolated stems (see Fig. 117). Structures 

 of this character were to be seen in great number on roots of Cocos, 

 but it could not be said that an abnormal number had been produced, 

 for no exact comparisons could be made. No generalizations may 

 be made as to the behavior of these organs with respect to light and 

 darkness in view of the insufficient data at hand. 



Epidermal Cells of Etiolated Stems. — Epidermal cells were 



