Chap. XI. MALE ELEMENT ON THE MOTHER-FORM. 433 



certain nnmljcr of the seeds, as in the case of the pea, or only 

 a part of the ovarium, as with the striped orange, mottled 

 grapes, and maize, is thus affected. It must not be supposed 

 that any direct or immediate eflFect invariably follows the 

 use of foreign pollen : this is far from being the case ; nor 

 is it known on what conditions the result dejiends. Mr. 

 Knight^** expressly states that he has never seen the fruit 

 thus affected, though he crossed thousands of apple and other 

 fruit-trees. 



There is not the least reason to believe that a branch which 

 has borne seed or fruit directly modified by foreign pollen is 

 itself affected, so as afterwards to produce modified buds ; 

 such an occurrence, from the temporary connection of the 

 flower with the stem, would be hardly possible. Hence, but 

 very few, if any, of the cases of bud- variation in the fruit of 

 trees, given in the early part of this chapter can be accounted 

 for by the action of foreign pollen ; for such fruits have 

 commonly been propagated by budding or grafting. It is 

 also obvious that changes of colour in flowers, which neces- 

 sarily supervene long before they are ready for fertilisation, 

 and changes in the shape or colour of leaves, when due to the 

 appearance of modified buds, can have no relation to the 

 action of foreign pollen. 



The proofs of the action of foreign pollen on the motlier- 

 plant have been given in considerable detail, because this 

 action, as we shall see in a future chapter, is of the highest 

 theoretical importance, and becaiise it is in itself a remarkable 

 and apparently anomalous circumstance. That it is remark- 

 able under a physiological point of view is clear, for the 

 male element not only afi"ects, in accordance with its proj^er 

 function, the germ, but at the same time various parts of the 

 mother-plant, in the same manner, as it affects the same part 

 in the seminal offspring from the same two parents. We thus 

 learn that an ovule is not indispensable for the reception of 

 the influence of the male element. But this direct action of 

 the male element is not so anomalous as it at first appears, 

 for it comes into play in the ordinary fertilisation of many 



'^' 'Transact, of Hort. Soc.,* vol. v. p. 68. 

 VOL. I. 2 ? 



