150 A Defence of Mendel's 



I have grown a "grey" pea and noticed that the seed-coats 

 ripened in my garden differ considerably and not quite 

 uniformly from those received from and probably ripened 

 in France, mine being mostly pale and greyish, instead 

 of reddish-brown. We have elsewhere seen (p. 120) that 

 pigments of the seed-coat-colour may be very sensitive to 

 conditions, and slight differences of moisture, for example, 

 may in some measure account for the differences in colour. 

 Among my crosses I have a pod of such " grey " peas ferti- 

 lised \sy Laxton' s Alpha (green cotyledons, coat transparent). 

 It contained five seeds, of which four were red-brown on 

 one side and grey with purple specks on the other. The 

 fifth was of the grey colour on both sides. I regard this 

 difference not as indicating segregation of character but 

 merely as comparable with the difference between the two 

 sides of a ripe apple, and I have little doubt that Correns' 

 case may be of the same nature*. Phenomena somewhat 

 similar to these will be met with in Laxton's case of the 

 " maple " seeded peas (see p. 161). 



2. Seed-shapes. Here Professor Weldon has three sets 

 of alleged exceptions to the rule of dominance of round 

 shape over wrinkled. The first are Rimpau's cases, the 

 second are Tschermak's cases, the third group are cases of 

 " grey " peas, which we will treat in a separate section (see 

 pp. 153 and 158). 



(a) Rimpau's cases. Professor Weldou quotes Rimpau 

 as having crossed wrinkled and round peast and found 



* Mr Hurst, of Burbage, tells me that in varieties having coats 

 green or white, e.g. American Wonder, the white coats are mostly 

 from early, the green from later pods, the tints depending on 

 conditions and exposure. 



t In the first case Knight's Marrow with Victoria, both ways ; in 

 the second Victoria with Telephone, both ways. 



