May, 1919] Nature of Diecious Condition 413 



and female organs or gametes, for all such factors are present 

 in these cells; nor is there any relation to a reduction division, 

 nor to any other possible shifting of hereditary sexual units. 

 All of the sexual hereditary factors are present and functioning 

 at certain points in cells derived by vegetative division from a 

 previous, common, mother cell. 



This interesting example shows that a sex reversal can and 

 sometimes does take place in an old tissue whose cells are 

 removed by thousands of vegetative divisions from the original 

 zygote. It assures us that sex control is only a matter of finding 

 out how to change the prevailing physiological state of the 

 tissues in some way corresponding to the change of state which 

 actually takes place in living bodies without any apparent 

 external cause. It is reasonable to believe that a change in 

 sexual state could be accomplished much more readily in the 

 zygote, or the cells coming immediately from it, than in an 

 older tissue where the particular condition presumably has been 

 intensified by its longer continuance, whether the state is due 

 to accumulated chemical bodies or to some other cause. 



Salix amygdaloides Anders. 



During the same period, the writer studied the diecious 

 nature of the peachleaf willow, Salix amygaloides Anders., 

 on the same farm. There is a grove of about 100 trees which 

 has developed in a ravine that was formerly pure prairie, 

 within the memory of the writer. One cannot be certain of 

 the exact number of individuals, as this species sprouts abun- 

 dantly from the base and forms clumps of shoots or trees which 

 have a common vegetative origin. In older specimens it is 

 not possible to tell absolutely whether a given clump represents 

 a single individual or two or more. 



Out of the 100 trees 9 individuals were found intermediate 

 while the rest seemed to be normal staminate or carpellate. 

 However, since the study was begun rather late in the blooming 

 period there may have been some apparently carpellate indi- 

 viduals that had previously produced staminate catkins. The 

 study was, therefore, confined to the nine intermediate indi- 

 viduals discovered. From a superficial knowledge of this 

 species of willow, the writer beheves that intermediates are 

 quite rare and not commonly produced as in the white mulberry. 



All of the nine intermediate individuals seemed to be pri- 

 marily staminate, ranging from a few to many carpellate cat- 



