322 



Mendel's Experiments 



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 terminal, 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 character for each, in so far that 

 healthy plants, grown in the same soil, are only subject 

 to unimportant variations in this character. 



In experiments with this character, in order to be able 

 to discriminate with certainty, the long axis of 6 to / ft. was 

 always crossed with the short one off ft. to \\ ft. 



Each two of the differentiating characters enumerated 

 above were united by cross-fertilisation. There were made 

 for the 



ist trial 60 fertilisations on 15 plants. 



2nd 

 3rd 

 4th 

 5th 

 6th 

 yth 



58 

 35 

 40 



23 

 34 



37 



5 



10 

 10 



* 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.] 



t [This is often called the Mummy Pea. It shows slight fasciation. 

 The form I know has white standard and salmon-red wings.] 



\ [In my account of these experiments (R.H.S. Journal, vol. xxv. 

 p. 54) I misunderstood this paragraph and took "axis" to mean the floral 

 axis, instead of the main axis of the plant. The unit of measurement, 

 being indicated in the original by a dash ( ' ), I carelessly took to have 

 been an inch, but the translation here given is evidently correct.] 



