526 BOTANICAL GAZETTE [December 



suggests that these studies indicate that "the gene for fasciation 

 appears to me to lie deeper in sporogenesis than the chromosome ." 

 "The abnormal character development appears most easily inter- 

 preted from a physiological standpoint." Whether or not his 

 contention is correct that "physiological" factors rather than 

 chromosomes control the continuous fasciation through the chain 

 of alternation of generations, there can be no question, however, 

 regarding the fact that some physiological factor, notably sap 

 pressure, is intimately associated with the control of the fascia- 

 tion of ash, willow, and cottonwood on stems found on tree 

 stumps in the North Dakota tree claim. 



The examples of fasciation presented in this paper have been 

 noted because of the bearing which the study of abnormal struc- 

 tures may have upon the study of normal morphological structures; 

 and also because of the possible interesting physiological relation 

 existing between increased sap pressure and the disturbed balance 

 of forces which are believed to be responsible for cottonwoods and 

 willows undergoing a change from radial to more or less bilateral 

 symmetry of stem during their first three seasons of growth. 



University of Idaho 

 Moscow, Idaho 





