122 A Defence of Mendel's 



There are some varieties which have cotyledons green 

 and intermediate shading to greenish yellow, like Stratagem 

 quoted by Professor Weldon. Others have yellow and 

 intermediate shading to yellowish green, such as McLean's 

 Best of all* . I am quite disposed to think there may be 

 truly monomorphic varieties with cotyledons permanently 

 of intermediate colour only, but so far I have not seen 

 onet. The variety with greatest irregularity (apart from 

 regular dimorphism) in cotyledon-colour I have seen is a 

 sample of ''''mange-tout a rames, a grain vert," but it was a 

 good deal injured by weevils (Bruchus), which always cause 

 irregularity or change of colour. 



Lastly in some varieties there are many piebalds or 

 mosaics. 



From what has been said it will be evident that the 

 description of a pea in an old book as having been green, 

 blue, white, and so forth, unless the cotyledon-colour is 

 distinguished from seed-coat colour, needs careful con- 

 sideration before inferences are drawn from it. 



Shape. 



t 



In regard to shape, if we keep to ordinary shelling peas, 

 the facts are somewhat similar, but as shape is probably 

 more sensitive to conditions than cotyledon-colour (not 

 than seed-coat colour) there are irregularities to be perhaps 

 ascribed to this cause. Broadly, however, there are two 

 main divisions, round and wrinkled. It is unquestioned 

 that between these two types every intermediate occurs. 



* I notice that Vilrnorin in the well-known Plantes Potageres, 

 1883, classifies the intermediate-coloured peas with the green. 



f Similarly though tall and dwarf are Mendelian characters, peas 

 occur of all heights and are usually classified as tall, half-dwarfs, and 

 dwarfs. 



