MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



223 



trachten oder besser ware es vielleicht, sie als solche zu bezeichnen, 

 deren Langenwachstum durch das Licht nicht wesentlich beeinflusst 

 wird." '"^ He seems to have lost sight of the differences in behavior 

 among the internodes and to have transferred his idea of " natural 

 etiolation " to include the entire stems. The measurements of etio- 

 lated and normal internodes given by him show that certain inter- 

 nodes in the stem of any given species undergo excessive elongation 

 in darkness and others do not. His observations in this matter are 



Fk;. 164. Ipomca purpurea, with terminal portion of twining stem enclosed in a 

 dark chamber illustrating the method bj' which " partial etiolations " are produced. 

 Redrawn, after Sachs. 



confirmed by many others including my own, and it seems quite 

 evident that the occurrence and position of internodes undergoing 

 etiolative elongation are characteristic of the species and may have 

 some connection with its general habit, and that no stem is to be re- 

 garded as " normally " etiolated. 



"'Sachs. Ueber den Einfluss des Tageslichts auf Neubildung und Entfaltung 

 verschiedener Pflanzenorgane. Bot. Zeitung, 21 : Beilage, p. 31. 1863. 



