APPENDIX 317 



The characters which were selected for experiment relate: 



1. To the difference in tlieform of the ripe seeds. These are eithet 

 round or roundish, the depressions, if any, occur on the surface, 

 being always only shallow; or they are irregularly angular and 

 deeply wrinkled (P. quadratum). 



2. To the difference in the colour of the seed albumen (endosperm) .^ 

 The albumen of the ripe seeds is either pale yellow, bright yellow 

 and orange coloured, or it possesses a more or less intense green 

 tint. This difference of colour is easily seen in the seeds as [ = if] 

 their coats are transparent. 



3. To the difference in the colour of the seed-coat. This is either 

 white, with which character white flowers are constantly corre- 

 lated; or it is grey, grey-brown, leather-brown, with or without 

 violet spotting, in which case the colour of the standards is violet, 

 that of the wings purple, and the stem in the axils of the leaves is of 

 a reddish tint. The grey seed-coats become dark brown in boiling 

 water. 



4. To the difference in the form of the ripe pods. These are 

 either simply inflated, not contracted in places; or they are deeply 

 constricted between the seeds and more or less wrinkled (P. 

 saccharatum) . 



5. To the difference in the colour of the unripe pods. They are 

 either light to dark green, or vividly yellow, in which colouring the 

 stalks, leaf- veins, and calyx participate.^ 



6. To the difference in the position of the flowers. They are either 

 axial, that is, distributed along the main stem; or they are ter- 

 minal, that is, bunched at the top of the stem and arranged almost 

 in a false umbel; in this case the upper part of the stem is more or 

 less widened in section (P. umbellatum) .^ 



7. To the difference in the length of the stem. The length of the 

 stem ^ is very various in some forms; it is, however, a constant 



^ [Mendel uses the terms " albumen " and " endosperm " somewhat loosely to 

 denote the cotyledons, containing food-material, within the seed.] 



"^ One species possesses a beautifully brownish-red coloured pod, which when 

 ripening turns to violet and blue. Trials with this character were only begun last 

 year. [Of these further experiments it seems no account was published. Correns has 

 since worked with such a variety.] 



^ [This is often called the Mummy Pea. It shows slight fasciation. The form 

 1 know has white stan<lard and salmon-red wings.] 



■• [In my account of these experiments {li.H.8. Journal, vol. xxv. p. 54) I mis- 

 understood this paragraph and took '* axis " to mean the floral axis, instead of the 



