Principles of Heredity 155 



that according as a round sativum or the Graue Riesen is 

 used as mother, the first-cross seeds "will be round and 

 smooth or flattened and wrinkled." 



As a matter of fact, however, the seeds of Graue Riesen 

 though slightly wrinkled do not belong to the "wrinkled" 

 class; but if the classification "wrinkled" and "round" is 

 to be extended to such peas at all, they belong to the round. 

 Mendel is careful to state that his round class are " either 

 spherical or roundish, the depressions on the surface, when 

 there are any, always slight " ; while the " wrinkled " class 

 are "irregularly angular, deeply wrinkled*." 



On this description alone it would be very likely that 

 Graue Riesen should fall into the round class, and as such 

 it behaves in its crosses, being dominant over wrinkled 

 (see Nos. 3 and 6, below). I can see that in this case 

 Professor Weldon has been partly misled by expressions 

 of Tschermak's, but the facts of the second generation 

 should have aroused suspicion. Neither author notices 

 that as all five varieties crossed by Tschermak with Graue 

 Riesen were round, the possibilities are not exhausted. 

 Had Tschermak tried a really wrinkled sativum with Graue 

 Riesen he would have seen this obvious explanation. 



As some of my own few observations of first-crosses bear 

 on this point I may quote them, imperfect though they are. 



I grew the purple-flowered sugar-pea " Pois sans par- 

 chemin geant a tres large cosse" a soft-podded "mange- 

 tout" pea, flowers and seed-coats coloured, from Vilniorin's, 

 probably identical with Graue Riesen. 



1. One flower of this variety fertilised with Pois tres 

 nain de Bretagne (very small seed; yellow cotyledons ; very 



"Entweder kugelrund oder rundlich, die Einsenkungen, wenn 

 welche an der OberflcicJie vorkommen, immer nur seicht, oder sie sind 

 unregelmcissig kantig, tief runzlig (P. quadratum)." 



