478 



Other flowers are sterile owing to the peculiar way they 

 expand. Instead of the petals unfolding from the base as shown 

 in Fig. 5, they open rose-like from the top, and when they thus 

 open, there is no jerk and no scattering of pollen, and consequently 

 bad setting ; or it happens that the stamens remain stuck to the 

 petals and are shorter than the pistil, and are not able to reach up 

 to the gummy secretion on the stigma. 



The various floral organs, moreover, undergo at times modifica- 

 tions which prove obstacles to their fertilisation. Thus whole 



bunches are seen to turn into 

 tendrils ; or, owing to a thickening 

 of any one of the floral organs, the 

 flower assumes the appearance of 

 being double. Such flowers are 

 always sterile. 



All these structural defects 

 are hereditary and liable to be 

 transmitted through cuttings, hence 

 the importance of eliminating such 

 vines from a vineyard by grafting 

 on them scions from fertile vines, 

 and also the advisability of reject- 

 ing any cutting from them for the 

 purpose of planting. Other con- 

 stitutional causes as well influence 

 the bearing of vines and lead to 

 imperfect setting. 



The bunches are loose and 

 contain berries of various sizes 

 with numerous blanks between. A 

 lowering of the vitality of the 

 plant consequent upon attacks of 

 oidium, or other fuugous diseases, 

 predisposes vines to this form of 

 bad setting. 



This accident may also be 

 caused by a sudden drop in the tein- 

 perature, by continuous rain at 

 blossoming time, or by hot blasts 

 of drying wind. Although a f < w 



berries which set properly grow to their full size, numerous small 

 ones never grow very large, and are devoid of seeds. They ripen 

 and are as sweet as the others. The Black Morocco grape is 

 particularly subject to this form of bad setting or shanking. The 

 explanation given of this peculiarity is that for one or other of 

 the causes mentioned above, a few flowers only set and the others 

 are blighted. A number of the more backward blossoms which 

 generally fail to set when the first blossoms have turned into 

 fruit then open and form fruit. These, however, located on the 



FIG. 11. Double flowers. 



