ilfr Gompton, On Right- and Left- Handedness in Barley. 505 



It is true that this table does not reach the same degree of 

 precision as that attained in the previous discussion, the numbers 

 recorded being smaller. But there appears to be no reason to 

 doubt its substantial accuracy. The ratios given by the offspring 

 of right- and left-handed seedlings respectively are so nearly the 

 same that it seems impossible to detect any hereditary nexus 

 between successive generations. The fact that the proportion of 

 R.H. seedlings produced from (self- fertilised) left-handed plants is 

 slightly greater than that produced from (self-fertilised) right- 

 handed plants seems to emphasise this negative answer to the 

 problem. 



The absence of influence of the first leaf on the ratio given 

 by the spike, taken with the similar absence of influence of the 

 last leaf (p. 501), leads to the conclusion that these vegetative 

 characters of the parent plant do not govern the ratio of rights to 

 lefts among the offspring. 



Conclusion. 



We are confronted with the fact that a random collection of a 

 reasonable number of barley seeds always produces, so far as 

 known, an excess of seedlings with the first leaf twisted in what 

 may be called the left-handed direction. The ratio of lefts to 

 rights in the case of " Plumage Corn " (the variety most accu- 

 rately studied) approximates very closely to 1*5; in other varieties 

 similar or smaller ratios are found. 



Statistics show that : 



(i) The twist of the last leaf below a spike has no influence 

 whatever on the ratio of right- to left-handed seedlings produced 

 from that spike. 



(ii) The same ratio subsists among the seedlings whether 

 produced from the odd or even rows of seed on the parent ear : 

 and no orderly arrangement of seedlings with respect to the twist 

 of the first leaf could be detected on the ear. 



(iii) The ratio among the seedlings is not governed by the 

 twist of the first leaf of the parent plant : i.e. the characters of 

 right- and left-handedness in barley appear not to be hereditary. 



Thus the reason for the production of the excess of left- 

 handed seedlings remains an unsolved problem. It seems clear 

 that the cause of this constant excess must be one of some 

 subtlety, such as is usually classed as "accidental." It is possible, 

 of course, to assume that barley is genetically left-handed, and 

 that a constant proportion (in "Plumage Corn" 40°/^) of "acci- 

 dental " reversals occur in every population and in each generation. 

 This explanation would cover the observed facts : but it would 



