CHAP. VII. TABLE A. 273 



been about as many cases of self-fertilised plants 

 exceeding the crossed in height by above five per cent, 

 as of the crossed thus exceeding the self-fertilised ; but 

 we see that of the latter there are fifty-seven cases, and 

 of the former only eight cases ; so that the cases in 

 which the crossed plants exceed in height the self- 

 fertilised in the above proportion are more than seven 

 times as numerous as those in which the self-fertilised 

 exceed the crossed in the same proportion. For our 

 special purpose of comparing the powers of growth 

 of crossed and self-fertilised plants, it may be said 

 that in fifty-seven cases the crossed plants exceeded 

 the self-fertilised by more than five per cent., and that 

 in twenty-six cases (18 + 8) they did not thus exceed 

 them. But we shall now show that in several of these 

 twenty-six cases the crossed plants had a decided ad- 

 vantage over the self-fertilised in other respects, though 

 not in height ; that in other cases the mean heights 

 are not trustworthy, owing to too few plants having 

 been measured, or to their having grown unequally 

 from being unhealthy, or to both causes combined. 

 Nevertheless, as these cases are opposed to my general 

 conclusion I have felt bound to give them. Lastly, the 

 cause of the crossed plants having no advantage over 

 the self-fertilised can be explained in some other cases. 

 Thus a very small residue is left in which the self- 

 fertilised plants appear, as far as my experiments 

 serve, to be really equal or superior to the crossed 

 plants. 



We will now consider in some little detail the eigh- 

 teen cases in which the self-fertilised plants equalled 

 in average height the crossed plants within five per 

 cent. ; and the eight cases in which the self-fertilised 

 plants exceeded in average height the crossed plants 

 by above five per cent. ; making altogether twenty-six 



