60 IPOMCEA PURPUREA. Chap. IL 



fertilised plants. It is therefore clear that a cross between the 

 self-fertilised children of Hero did not produce any beneficial effect 

 worth notice ; and it is very doubtful whether this negative result 

 can be attributed merely to the fact of brothers and sisters having 

 been united, for the ordinary intercrossed plants of the several 

 successive generations must often have been derived from the 

 union of brothers and sisters (as shown in Chap. I.), and yet all 

 of them were greatly superior to the self-fertilised plants. We 

 are therefore driven to the suspicion, which we shall soon see 

 strengthened, that Hero transmitted to its offspring a peculiar 

 constitution adapted for self-fertilisation. 



It would appear that the self-fertilised descendants of Hero 

 have not only inherited from Hero a power of growth equal to 

 that of the ordinary intercrossed plants, but have become more 

 fertile when self-fertilised than is usual with the plants of the 

 present species. The flowers on the self-fertilised grandchildren 

 of Hero in Table XVI. (the eighth generation of self-fertilised 

 plants) were fertilised with their own pollen and produced plenty 

 of capsules, ten of which (though this is too few a number for a 

 safe average) contained 5-2 seeds per capsule, a higher average 

 than was observed in any other case with the self-fertilised plants. 

 The anthers produced by these self-fertilised grandchildren were 

 also as well developed and contained as much pollen as those on 

 the intercrossed plants of the corresponding generation ; whereas 

 this was not the case with the ordinary self-fertilised plants of 

 the later generations. Nevertheless some few of the flowers 

 produced by the grandchildren of Hero were slightly monstrous, 

 like those of the ordinary self-fertilised plants of the later genera- 

 tions. In order not to recur to the subject of fertility, I may add 

 that twenty-one self-fertilised capsules, spontaneously produced 

 by the great-grandchildren of Hero (forming the ninth generation 

 of self-fertilised plants), contained on an average 4*47 seeds ; and 

 this is as high an average as the self-fertilised flowers of any 

 generation usually yielded. 



Several flowers on the self-fertilised grandchildren of Hero in 

 Table XVI. were fertilised with pollen from the same flower ; and 

 the seedlings raised from them (great-grandchildren of Hero) 

 formed the ninth self-fertilised generation. Several other flowers 

 were crossed with pollen from another grandchild, so that they 

 may be considered as the offspring of brothers and sisters, and the 

 seedlings thus raised may be called the intercrossed great-grand- 

 children. And lastly, other flowers were fertilised with pollen 



