266 



REV. J. T. GULICK ON DIVERGENT EYOLUTlON 



thus raised may be called the Colchester-crossed great-grand- 

 children. In my anxiety to see what the result would be, I 

 unfortunately planted the three lots of seeds (after they had 

 germinated on sand) in the hothouse in the middle of winter, 

 and in consequence of this the seedlings (twenty in number of 

 each kind) became very unhealthy, some growing only a few 

 inches in height, and very few to their proper height. The 

 result, therefore, cannot be fully trusted ; and it would be 

 useless to give the measurements in detail. In order to strike 

 as fair an average as possible, I first excluded all the plants 

 under 50 inches in height, thus rejecting all the most unhealthy 

 plants. The six self-fertilized thus left were on an average 66*86 

 inches high, the eight intercrossed plants 63*2 high, and the 

 seven Colchester-crossed 65*37 high ; so that there was not 

 much difference between the three sets, the self -fertilized plants 

 having a slight advantage. Nor was there any great difference 

 when only the plants under 36 inches in height were excluded. 

 Nor, again, when all the plants, however much dwarfed and 

 unhealthy, were included. 



" In this latter case the Colchester-crossed gave the lowest 

 average of all ; and if these plants had been in any marked 

 manner superior to the other two lots, as from my former 

 experience I fully expected they would have been, I cannot but 

 think that some vestige of such superiority would have been 

 evident, notwithstanding the very unhealthy condition of most 

 of the plants. No advantage, as far as we can judge, was 

 derived from intercrossing two of the grandchildren of Hero^ 

 any more than when two of the children were crossed. It 

 appears therefore that Hero and its descendants have varied 

 from the common type, not only in acquiring great power of 

 growth and increased fertility when subjected to self-fertilization, 

 but in not profiting from a cross with a distinct stock ; and this 

 latter fact, if trustworthy, is a unique case, as far as I have 

 observed in all my experiments." * 



Let us now consider for a moment what must be the result 

 when such a variation occurs in a wild species subject to the 

 ordinary conditions of competition. In the first place, it would 

 gradually prevail over other representatives of the same local 

 stock, both by its more vigorous growth and by its greater 



* Cross- and Self-Fertilization in tlie Vegetable Kingdom,' pp. 50, 61. 



