Principles of Heredity 153 



3. Other phenomena, especially regarding seed-shapes, 

 in the case of "grey" peas. Modern evidence. Professor 

 Welclon quotes from Tschermak the interesting facts about 

 the "grey' pea, Graue Riesen, but does not attempt to 

 elucidate them. He is not on very safe ground in adducing 

 these phenomena as conflicting with the "law of dominance." 

 Let us see whither we are led if we consider these cases. 

 On p. 124 I mentioned that the classes round and wrinkled 

 do not properly hold if we try to extend them to large- 

 seeded sorts, and that these cases require separate con- 

 sideration. In many of such peas, which usually belong 

 either to the classes of sugar-peas (mange-touts} or " grey ' : 

 peas (with coloured flowers), the seeds would be rather 

 described as irregularly indented, lumpy or stony*, than by 

 any use of the terms round or wrinkled. One sugar-pea 

 (Debarbieux) which I have used has large flattish, smooth, 

 yellow seeds with white skins, and this also in its crossings 

 follows the rules about to be described for the large-seeded 

 "grey" peas. 



In the large " grey " peas the most conspicuous feature 

 is the seed-coat, which is grey, brownish, or of a bright 

 reddish colour. Such seed-coats are often speckled with 

 purple, and on boiling these seed-coats turn dark brown. 

 They are in fact the very peas used by Mendel in making 

 up his third pair of characters. Regarding them Professor 



' Gartner's macrospermurn was evidently one of these, though 

 from the further account (p. 498) it was probably more wrinkled. 

 There are of course mange-touts which have perfectly round seeds. 

 Mendel himself showed that the mange-tout character, the soft 

 constricted pod, was transferable. There are also mange-touts with 

 fully wrinkled seeds and "grey" peas with small seeds (see Vilmorin- 

 Andrieux, Plantes Potageres, 1883). 



