Experimental Pedigree-Cultures 549 



I have made four such experiments, each com- 

 prising the handling of many thousands of in- 

 dividual plants, and lasting through ^ve to nine 

 generations. At the beginning the plants were 

 biennial, as in the native locality, but later I 

 learned to cultivate them in annual genera- 

 tions. They have been started from different 

 plants and seeds, introduced from the original 

 field into my garden at Amsterdam. 



It seems sufficient to describe here one of 

 these pedigree-cultures, as the results of all four 

 were similar. In the fall of 1886 I took nine 

 large rosettes from the field, planted them to- 

 gether on an isolated spot in the garden, and 

 harvested their seeds the next year. These nine 

 original plants are therefore to be considered 

 as constituting the first generation of my race. 

 The second generation was sown in 1888 and 

 flowered in 1889. It at once yielded the ex- 

 pected result. 15000 seedlings were tested 

 and examined, and among them 10 showed 

 diverging characters. They were properly 

 protected, and proved to belong to two new 

 types. 5 of them were lata and 5 nanella. 

 They flowered next year and displayed all the 

 characters as described in our preceding lec- 

 ture. Intermediates between them and the gen- 

 eral type were not found, and no indication of 

 their appearance was noted in their parents. 



