CHAP. VII. TABLE O. 265 



observations (not made with great care) the offspring 

 from crossed varieties were to self-fertilised plants in 

 height, in one case as 100 to about 75, and in a second 

 case as 100 to 60. 



(8.) Lathy rus odoratus. The sweet-pea is in the 

 same state in regard to self-fertilisation as the common 

 pea ; and we have seen that seedlings from a cross 

 between two varieties, which differed in no respect 

 except in the colour of their flowers, were to the self- 

 fertilised seedlings from the same mother-plant in 

 height as 100 to 80 ; and in the second generation as 

 100 to 88. Unfortunately I did not ascertain whether 

 crossing two plants of the same variety failed to pro- 

 duce any beneficial effect, but I venture to predict such 

 would be the result. 



(9.) Petunia violacea. The intercrossed plants of 

 the same stock in four out of the five successive gene- 

 rations plainly exceeded in height the self-fertilised 

 plants. The latter in the fourth generation were 

 crossed by a fresh stock, and the seedlings thus obtained 

 were put into competition with the self-fertilised plants 

 of the fifth generation. The crossed plants exceeded 

 the self-fertilised in height in the ratio of 100 to 66, 

 and in weight as 100 to 23; but this difference, 

 though so great, is not much greater than that between 

 the intercrossed plants of the same stock in comparison 

 with the self-fertilised plants of the corresponding 

 generation. This case, therefore, seems at first sight 

 opposed to the rule that a cross with a fresh stock is 

 much more beneficial than a cross between individuals 

 of the same stock. But as with Eschscholtzia, the 

 reproductive system was here chiefly benefited ; for 

 the plants raised from the cross with the fresh stock 

 were to the self-fertilised plants in fertility, both lots 

 being naturally fertilised, as 100 to 46, whereas the 



