PETALIZATION IN THE JAPANESE QUINCE 



Albert A. Hansen 

 U. S. Department of Agriculture, Washington, D. C. 



EVERY one has frequently won- 

 dered just why a cultivated rose 

 should possess an abundance of 

 petals, whereas the wild rose 

 usually has but five petals. To fully 

 understand this phenomenon, funda- 

 mental explanations may be of great 

 assistance. 



It is well known that a leaf bud is 

 simply a tiny branch bearing a number 

 of tiny leaves; when the miniature 

 branch expands and grows the surround- 

 ing bud bracts drop and the leaves en- 

 large. In such plants as the horse- 

 chestnut the number of leaves contained 

 in the bud is frequently the same as the 



number of leaves appearing on the 

 resulting developed branch. 



In a similar manner there is reason to 

 consider a flower bud as a tiny branch 

 containing leaves, differing in that the 

 stem remains practically the same length 

 throughout the entire life of the flower; 

 i. e. , the stem remains shortened instead 

 of elongating, as was the case with the 

 stem in the leaf bud. Upon this -nuch 

 shortened stem are groups of leaves, 

 mostly highly modified; in its fullest 

 expression a typical flower contains leaf 

 groups known as sepals, petals, stamens, 

 and pistils. 



The plasticity of these leaf groups is 



COMPLETE SERIES FROM PETAL TO ANTHER 



A complete series is h^re represented, starting with a perfect petal to the left. By gradaal 

 stages, petals with remnants of the anther lobe attached are reached and next may be noted 

 an anther which has become slightly petaloid, while on the extreme right is the perfect 

 stamen. With the progressive petalization of the filaments, the anther shows less and 

 less development, finally disappearing entirely. (i'''ig. 5.) 



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