CHAP. III. THUNBERGIA ALATA. 97 



germinating seeds were planted on opposite sides of five pots ; 

 and exactly half the crossed and half the self-fertilised plants 

 exceeded their opponents in height. Two of the self-fertilised 

 plants died young, before they were measured, and their crossed 

 opponents were thrown away. The six remaining pairs grew 

 very unequally, some, both of the crossed and self-fertilised 

 plants, being more than twice as tall as the others. The average 

 height of the crossed plants was 60 inches, and that of the self- 

 fertilised plants 65 inches, or as 100 to 108. A cross, therefore, 

 between distinct individuals here appears to do no good ; but 

 this result deduced from so few plants in a very sterile condition 

 and growing very unequally, obviously cannot be trusted. 



