CHAP. VL CROSS WITH A FRESH STOCK. 211 



thus raised may be called the Kew-crossed. Some other flowers 

 on the same two plants were fertilised with their own pollen, 

 and the seedlings thus raised form the fourth self-fertilised 

 generation. The crossed capsules produced by the plant in 

 Pot II., Table LXXXVH., were plainly less fine than the self- 

 fertilised capsules on the same plant. In Pot V. the one finest 

 capsule was also a self-fertilised one; but the seeds produced 

 by the two crossed capsules together exceeded in number those 

 produced by the two self-fertilised capsules on the same plant. 

 Therefore as far as the flowers on the parent-plants are con- 

 cerned, a cross with pollen from a fresh stock did little or no 

 good ; and I did not expect that the offspring would have re- 

 ceived any benefit, but in this I was completely mistaken. 



The crossed and self-fertilised seeds from the two plants were 

 placed on bare sand, and very many of the crossed seeds of both 

 sets germinated before the self-fertilised seeds, and protruded 

 their radicles at a quicker rate. Hence many of the crossed 

 seeds had to be rejected, before pairs in an equal state of germina- 

 tion were obtained for planting on the opposite sides of sixteen 

 large pots. The two series of seedlings raised from the parent- 

 plants in the two Pots II. and V. were kept separate, and when 

 fully grown were measured to the tips of their highest leaves, as 

 shown in the following double table. But as there was no uniform 

 difference in height between the crossed and self-fertilised seed- 

 lings raised from the two plants, their heights have been added 

 together in calculating the averages. I should state that by the 

 accidental fall of a large bush in the greenhouse, several plants 

 in both the series were much injured. These were at once 

 measured together with their opponents and afterwards thrown 

 away. The others were left to grow to their full height, and 

 were measured when in flower. This accident accounts for the 

 small height of some of the pairs ; but as all the pairs, whether 

 only partly or fully grown, were measured at the same time, the 

 measurements are fair. 



The average height of the twenty-six crossed plants in the six- 

 teen pots of the two series is 63 '29, and that of the twenty- 

 six self-fertilised plants is 41 '67 inches; or as 100 to 66. The 

 superiority of the crossed plants was shown in another way, 

 for in every one of the sixteen pots a crossed plant flowered 

 before a self-fertilised one, with the exception of Pot VI. of the 

 second series, in which the plants on the two sides flowered 

 simultaneously. 



p 2 



