Chap. III. CROSSED AND SELF-FERTILISED PLANTS. 65 



were on an average half an inch high, the self-fertilised ones 

 were only a quarter of an inch high. When grown to their full 

 height under the above unfavourable conditions, the four tallest 

 crossed plants averaged 7 ' 62, and the four tallest self-fertilised 

 5 87 inches in height ; or as 100 to 77. Ten flowers on the crossed 

 plants were fully expanded before one on the self-fertilised 

 plants. A few of these plants of both lots were transplanted 

 into a large pot with plenty of good earth, and the self-fertilised 

 plants, not now being subjected to severe competition, grew 

 during the following year as tall as the crossed plants; but 

 from a case which follows it is doubtful whether they would 

 have long continued equal. Some flowers on the crossed plants 

 were crossed with pollen from another plant, and the capsules 

 thus produced contained a rather greater weight of seed than 

 those on the self-fertilised plants again self-fertilised. 



Crossed and self-fertilised Plants of the Second Generation. Seeds 

 from the foregoing plants, fertilised in the manner just stated, 

 were sown on the opposite sides of a small pot (I.) and came up 

 crowded. The four tallest crossed seedlings, at the time of 

 flowering, averaged 8 inches in height, whilst the four tallest 

 self-fertilised plants averaged only 4 inches. Crossed seeds 

 were sown by themselves in a second small pot, and self- 

 fertilised seeds were sown by themselves in a third small pot ; 

 so that there was no competition whatever between these two 

 lots. Nevertheless the crossed plants grew from 1 to 2 

 inches higher on an average than the self-fertilised. Both lots 

 looked equally vigorous, but the crossed plants flowered earlier 

 and more profusely than the self-fertilised. In Pot I., in which 

 the two lots competed with each other, the crossed plants flowered 

 first and produced a large number of capsules, whilst the 

 self-fertilised produced only nineteen. The contents of twelve 

 capsules from the crossed flowers on the crossed plants, and 

 of twelve capsules from self-fertilised flowers on the self-fertilised 

 plants, were placed in separate watch-glasses for comparison 

 and the crossed seeds seemed more numerous by half than the 

 self-fertilised. 



The plants on both sides of Pot I., after they had seeded, 

 were cut down and transplanted into a large pot with plenty of 

 good earth, and in the following spring, when they had grown 

 to a height of between 5 and 6 inches, the two lots were equal, 

 as occurred in a similar experiment in the last generation. 

 But after some weeks the crossed plants exceeded the self- 



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