SOME COMMON BOTANICAL ERRORS 147 



parts of a vegetative shoot, but independent structures 

 of long ancestry and independent dignity. 



Another common error is that of attempting to ho- 

 mologize the parts of the stamen and of the carpel with 

 the parts of the green leaf. Thus, it is often said that 

 the filament represents the petiole, and the anther the 

 blade ; while in the carpels the ovary wall is said 

 to be the blade, the style the elongated tip, and the 

 stigma the extreme end turned back ; and much mental 

 ingenuity is needed to show how some of the more 

 specialized styles and stigmas fit into this scheme. In 

 fact, while the precise origin of the stamens and carpels 

 is not beyond doubt, this much is certain, that they are 

 the descendants of the sporophylls of cryptogamic 

 plants, and there is a very strong probability that these 

 sporophylls never have been green foliage leaves ; and 

 even if they were, it \vas at a time before the differ- 

 entiation of the modern specialized foliage leaf with its 

 blade, petiole, and stipules. It is, therefore, correct to 

 regard carpels and stamens as morphologically leaves ; 

 but they must be viewed as having followed a course 

 independent of that of foliage leaves, each developing 

 the parts necessary to its function without any regard 

 to the developments of the other. Hence it is not 

 possible to homologize the parts of one with the parts 

 of the other. 



Another very common error, perpetuated by its use in 

 all systematic works, is, that inferior ovaries represent 



