Still another type of flower is seen in the grapes that produce 

 seedless or nearly seedless fruits. Here the pistils are capable of 

 developing into fruits but the ovules, if present, do not develop into 

 seeds. According to Muller-Thurgau (1898), the fruits of the 

 seedless raisins develop under the stimulus of pollen-tube growth. 

 Pollination causes development of fruit but does not result in seed 

 formation. Such varieties as Sultana and Sultanina, therefore, are 

 fully seedless when grown under ample opportunity for both self- 

 and cross-pollination. This seems clearly to indicate that in the 

 fully seedless varieties no ovules capable of developing to full 

 maturity are present. Nothing definite seems to be known regarding 

 the exact origin of these seedless varieties and no seedless grape 

 has yet become of commercial value in the eastern United States. 

 The types of flowers which they possess have, however, been observed 

 among seedlings and are to be considered in judging the value of the 

 various flower types appearing in seedlings. 



It seems certain that the flowers borne by the greater number of 

 seedlings obtained in breeding grapes can be classed broadly as (1) 

 staminate, (2) perfect hermaphrodite, and (3) imperfect herma- 

 phrodite. No purely female types are known. For describing the 

 general heredity of sex in grapes, such a grouping is useful (Hedrick 

 and Anthony 1915, Detjen 1917). It has, however, been recognized 

 that a sharp distinction between these types does not exist. As 

 Booth (1902) remarks " the whole path is marked by transitional 

 forms; thus there are no distinct classes of self-sterile and self-fertile 

 grapes, but all gradations exist from one extreme to the other." 

 It is in the study and selection of these intergrading intersexual forms 

 that the possibility of finding types with the degree or kind of femaleness 

 which exists in the seedless types seems most promising. 



In continuing the studies of the inheritance of sex in grapes in 

 progress at the New York Agricultural Experiment Station, and 

 especially with reference to the production of the flower types that 

 give seedless fruits, it has seemed advisable to describe in more 

 detail the variations in the development of the flowers. A general 

 survey has revealed at least one new type of flower here designated 

 as having crinkled stamens, a wide range of variations in the length 

 of stamens among flowers classed as perfect hermaphrodites, and 

 various intermediates between the typically upright and the reflexed 



