1 58 A Defence of Menders 



are. And that is what Tschermak's Graue Riesen crosses 

 actually did, thereby exhibiting dominance in a very clear 

 form. To interject these cases as a mystery without pointing 

 out how easily they can be reconciled with the "law of 

 dominance" may throw an unskilled reader into gratuitous 

 doubt. 



Finally, since the wrinkled peas, Laxtons Alpha and 

 British Queen, pollinated by a large flat mange-tout, witness 

 Nos. 3 and 6 above, became round in both cases where this 

 experiment was made, we here merely see the usual domin- 

 ance of the non-wrinkled character ; though of course if a 

 roiwd-seeded. mother be used there can be no departure 

 from the maternal shape, as far as roundness is concerned. 



Correns' observations on the shapes of a "grey' pea 

 crossed with a round shelling pea, also quoted by Professor 

 Weldon as showing no dominance of roundness, are of 

 course of the same nature as those just discussed. 



C. Evidence of Knight and Laxton. 



In the last two sections we have seen that in using 

 peas of the "grey" class, i.e. with brown, red, or purplish 

 coats, special phenomena are to be looked for, and also 

 that in the case of large " indented " peas, the phenomena 

 of size and shape may show some divergence from that 

 simple form of the phenomenon of dominance seen when 

 ordinary round and wrinkled are crossed. Here the fuller 

 discussion of these phenomena must have been left to await 

 further experiment, were it not that we have other evidence 

 bearing on the same questions. 



The first is that of Knight's well-known experiments, 

 long familiar but until now hopelessly mysterious. I have 

 not space to quote the various interpretations which Knight 

 and others have put upon them, but as the Mendelian 



