Principles of Heredity 149 



the coats are usually highly coloured or orange-brown. 

 In reciprocal crosses Correns found no change from the 

 maternal seed-coat-colour or seed-shape. On sowing these 

 peas he obtained plants bearing peas which, using the 

 terminology of Mendel and others, he speaks of as the "first 

 generation." 



These peas varied in the colour of their seed-coats 

 from an almost colourless form slightly tinged with green 

 like the one parent to the orange-brown of the other 

 parent. The seeds varied in this respect not only from 

 plant to plant, but from pod to pod, and from seed to seed, 

 as Professor Correns has informed me. 



The peas with more highly-coloured coats were sown and 

 gave rise to plants with seeds showing the whole range of 

 seed-coat-colours again. 



Professor Weldon states that in this case neither the 

 law of dominance nor the law of segregation was observed ; 

 and the same is the opinion of Correns, who, as I under- 

 stand, inclines to regard the colour-distribution as indi- 

 cating a "mosaic' 1 formation. This is perhaps conceiv- 

 able ; and in that case the statement that there was no 

 dominance would be true, and it would also be true that 

 the unit of segregation, if any, was smaller than the in- 

 dividual plant and may in fact be the individual seed. 



A final decision of this question is as yet impossible. 

 Nevertheless from Professor Correns I have learnt one 

 point of importance, namely, that the coats of all these 

 seeds were thick, like that of the coloured and as usual 

 dominant form. There is no "mosaic" of coats like one 

 parent and coats like the other, though there may be a 

 mosaic of colours. In regard to the distribution of colour 

 however the possibility does not seem to me excluded that 

 we are here dealing with changes influenced by conditions. 



