CHAP. II. CROSS WITH A FRESH STOCK. 45 



The Effects on the Offspring of a Cross with a distinct 

 or fresh Stock belonging to the same Variety. From the 

 two foregoing series of experiments we see, firstly, the 

 good effects during several successive generations of 

 a cross between distinct plants, although these were 

 in some degree inter-related and had been grown 

 under nearly the same conditions ; and, secondly, the 

 absence, of all such good effects from a cross between 

 flowers on the same plant ; the comparison in both 

 cases being made with the offspring of flowers fertilised 

 with their own pollen. The experiments now to be 

 given show how powerfully and beneficially plants, 

 which have been intercrossed during many successive 

 generations, having been kept all the time under 

 nearly uniform conditions, are affected by a cross with 

 another plant belonging to the same variety, but to a 

 distinct family or stock, which had grown under dif- 

 ferent conditions. 



Several flowers on the crossed plants of the ninth generation 

 in Table X., were crossed with pollen from another crossed plant 

 of the same lot. The seedlings thus raised formed the tenth 

 intercrossed generation, and I will call them the " intercrossed 

 plants" Several other flowers on the same crossed plants ot 

 the ninth generation were fertilised (not having been castrated) 

 with pollen taken from plants of the same variety, but belonging 

 to a distinct family, which had been grown in a distant garden 

 at Colchester, and therefore under somewhat different conditions. 

 The capsules produced by this cross contained, to my surprise, 

 fewer and lighter seeds than did the capsules of the intercrossed 

 plants ; but this, I think, must have been accidental. The seed- 

 lings raised from them I will call the " Colchester-crossed." The 

 two lots of seeds, after germinating on sand, were planted in 

 the usual manner on the opposite sides of five pots, and the 

 remaining seeds, whether or not in a state of germination, 

 were thickly sown on the opposite sides of a very large pot, 

 No. VI., in Table XIII. In three of the six pots, after the 

 young plants had twined a short way up their sticks, one of the 



