Chap. VI. ON HETEEOSTYLED PLANTS. 263 



Now let us take a highly varying species with most 

 or all of the anthers exserted in some individuals, and 

 in others seated low down in the corolla; with the 

 stigma also varying in position in like manner. Insects 

 which visited such flowers would have different parts 

 of their bodies dusted with pollen, and it would be a 

 mere chance whether this were left on the stigma of 

 the next flower which was visited. If all the anthers 

 could have been placed on the same level in all the 

 plants, then abundant pollen would have adhered to 

 the same part of the body of the insects which fre- 

 quented the flowers, and would afterwards have been 

 deposited without loss on the stigma, if it likewise 

 stood on the same unvarying level in all the flowers. 

 But as the stamens and pistils are supposed to have 

 already varied much in length and to be still varying, 

 it might well happen that they could be reduced much 

 more easily through natural selection into two sets of 

 different lengths in different individuals, than all to the 

 same length and level in all the individuals. We know 

 from innumerable instances, in which the two sexes and 

 the young of the same species differ, that there is no 

 diffieulty in two or more sets of individuals being formed 

 which inherit different characters. In our particular 

 case the law of compensation or balancement (which 

 is admitted by many botanists) would tend to cause the 

 pistil to be reduced in those individuals in which the 

 stamens were greatly developed and to be increased in 

 length in those which had their stamens but little de- 

 veloped. 



Now if in our varying species the longer stamens 

 were to be nearly equalised in length in a considerable 

 body of individuals, with the pistil more or less reduced ; 

 and in another body, the shorter stamens to be simi- 

 larly equalised, with the pistil more or less increased in 

 19 



