22 



DIMORPHIC LEAVES IX RELATTOX TO HEREDITY. 



iiilieiitance seem to relax and tlie abnormal intermediate forms begin 

 to appear. They are much more common in the Egyptian cotton 

 than in the Upland and have shown themselves most frequently in a 

 peculiar fastigiate variety of the Egj'ptian cotton introduced into 

 Arizona under the name of ''Dale," perhaps the same as the variety 

 called "Bamieh" in Eg}^pt. 



Other series of abnormalities serve to connect the outer involucre of 

 the cotton flower with the inner involucre, or so-called calyx, as though 



Fig. 11.— Cotton leaf without lobes, a variation of the Triumph \arioty. 



(Natural size.) 



this organ were formed from another type of reduced and speciaUzed 

 leaves. The petals, on the contrary, seem to represent specialized 

 stamens rather than specialized leaves. They are inserted on the 

 base of the staminal colunm. I'licir development from stamens is 

 also suggested by the small, expanded, ])etal-like organs that are 

 sometimes found on the staminal colunm above the true petals. In 

 such a case the ])etals or the stamens might be said to be dimorphic, 

 or it might ])e consickMcd that there has been a failure of the normally 

 complete change in the expression of the characters in passing from 

 the petals to the stamens. 



221 



