J04 



IBERIS UMBELLATA. 



CHAP. 



does not look like it. Five seedlings from each lot of seeds were 

 raised, and the self-fertilised plants, when fully grown, exceeded 

 in average height by a trifle (viz. 4 of an inch) the five probably 

 crossed plants. I have thought it right to give this case and the 

 last, because had the supposed crossed plants proved superior 

 to the self-fertilised in height, I should have assumed without 

 doubt that the former had really been crossed. As it is, I do not 

 know what to conclude. 



Being much surprised at the two foregoing trials, I deter- 

 mined to make another, in which there should be no doubt about 

 the crossing. I therefore fertilised with great care (but as 

 usual without castration) twenty-four flowers on the supposed 

 crossed plants of the last generation with pollen from distinct 

 plants, and thus obtained twenty-one capsules. The self-fertilised 

 plants of the last generation were allowed to fertilise themselves 

 again under a net, and the seedlings reared from these seeds 

 formed the third self-fertilised generation. Both lots of seeds, 

 after germinating on bare sand, were planted in pairs on 

 the opposite sides of two pots. All the remaining seeds were 

 sown crowded on opposite sides of a third pot ; but as all the 

 self-fertilised seedlings in this latter pot died before they grew 

 to any considerable height, they were not measured. The 

 plants in Pots I. and II. were measured when between 7 and 

 8 inches in height, and the crossed exceeded the self-fertilised 

 in average height by 1 57 inches. When fully grown they were 

 again measured to the summits of their flower-heads, with the 

 following result : 



TABLE XXXI. 



