Chap. VIII. CROSSED AND SELF-FERTILISED PLANTS. 297 



intercrossed seedlings and seedlings of the seventh 

 self-fertilised generation were thus raised, and the 

 latter flowered before the intercrossed in three out of 

 the five pots. Flowers on a plant both of Mimulus 

 luteus and of Ipomoea purpurea were crossed with pollen 

 from other flowers on the same plant, and other flowers 

 were fertilised with their own pollen ; intercrossed 

 seedlings of this peculiar kind, and others strictly self- 

 fertilised being thus raised. In the case of the 

 Miniulus the self-fertilised plants flowered first in seven 

 out of the eight pots, and in the case of the Ipomoea 

 in eight out of the ten pots ; so that an intercross 

 between the flow3rs on the same plant was very far 

 from giving to the offspring thus raised, any advantage 

 over the strictly self-fertilised plants in their period 

 of flowering:. 



TJie Effects of crossing Flowers on the same Plant. 



In the discussion on the results of a cross with a fresh 

 stock, given under Table C in the last chapter, it was 

 shown that the mere act of crossing by itself does no 

 good ; but that the advantages thus derived depend on 

 the plants which are crossed, either consisting of 

 distinct varieties which will almost certainly differ 

 somewhat in constitution, or on the progenitors of the 

 plants which are crossed, though identical in every 

 external character, having been subjected to somewhat 

 different conditions and having thus acquired some 

 slight difference in constitution. All the flowers 

 produced by the same plant have been developed 

 from the same seed ; those which expand at the same 

 time have been exposed to exactly the same climatic 

 influences ; and the stems have all been nourished by 

 the same roots. Therefore in accordance with the con- 

 clusion just referred to, no good ought to result from 



