18 



DIMORPHIC LEAVES IN RELATION TO HEREDITY. 



toward the simple form of leaves. The seed, iinfortimately, had all 

 been picked, so that the inheritance of the variation could not be 

 tested. The plant appeared unusually vigorous, but had the advan- 

 tage of standing at the end of the row. Most of the leaves were 

 simple and entire (fig. 11), only a few being three lobed and these 

 with the lobes unusually short. A count showed 152 simple leaves 

 and 41 with lobes. Some of the wild species of cotton have all the 



Fig. 7.— Leaves of Upland cotton seedling from first seven nodes above the cotyledons, showing 



changes of form. (Natural size.) 



leaves simple, and thus complete the correspondence with the simple- 

 leaved Egyptian variety of Hibiscus cannahinus. 



The tendency to reduction of the lobes under greenhouse condi- 

 tions represents another phase of the general jxirallelism of leaf 

 forms. This tendency seems to be very general, not only in different 

 varieties of Upland cotton, but also in the Egyptian and Sea Island 

 types that in open-air conditions have the lo])os more highly tlcvel- 

 oped than those of Upland cotton. The fruiting branches of green- 



221 



