Experimental Pedigree-Cultures 551 



served that the attributes of lata and nanella, 

 which I now studied in the offspring of my first 

 mutants, were clearly discernible in extreme 

 youth, while those of rubrinervis remained con- 

 cealed some weeks longer. Hence I con- 

 cluded that*the young plants should be examined 

 from time to time until they proved clearly to be 

 onlv normal lamarckiana. Individuals ex- 

 hibiting any deviation from the type, or even 

 giving only a slight indication of it, were forth- 

 with taken out of the beds and planted separate- 

 ly, under circumstances as favorable as possible. 

 They were established in pots with well-manured 

 soil and kept under glass, but fully exposed to 

 sunshine. As a rule they grew very fast, and 

 could be planted out early in June. Some of 

 them, of course, proved to have been erroneous- 

 ly taken for mutants, but many exhibited new 

 characters. 



All in all I had 334 young plants which did 

 not agree with the parental tjipe. As I exam- 

 ined some 14000 seedlings altogether, the result 

 was estimated at about 2.5^. This proportion 

 is much larger than in the yields of the two first 

 generations and illustrates the value of im- 

 proved methods. No doubt many good muta- 

 tions had been overlooked in the earlier observa- 

 tions. 



As was to be expected, lata and nanella 



