MUTATIONS, VARIATIONS, AND RELATIONSHIPS OP THE OENOTHERAS. 59 



BUD-SPORTSVEGETATIVE SALTATIONS. 



One of the most interesting and least understood phases of heredity is that 

 in which the tract of embryonic tissue constituting a bud may develop and 

 put into external realization a set of characters wholly different from those of 

 the remainder of the individual. A large number of such instances have been 

 seen by gardeners, horticulturists, and farmers, although exact observations 

 on the hereditary qualities of such mutant branches are almost wholly want- 

 ing. In some cases the departure from the type does not affect the entire 

 branch, and it may not be made manifest until an advanced stage of its devel- 

 opment, causing some of the leaves or perhaps some of the flowers to show 

 atypic characters. When such partial vegetative saltation ensues it gen- 

 erally results in converting a lateral section of the branch or inflorescence into 

 the new form, and has been termed "sectorial variation" by De Vries. To 

 designate it beyond danger of misapprehension, however, it should be known 

 as sectorial bud-mutation. 



The cultures carried on in the experimental garden during 1905 were char- 

 acterized by two remarkable bud-sports. 



The hybrid O. lamarckiana X (0. lamarckiana X 0. cruciata') comprised 

 nearly a score of recognizable forms in the seedling stage. About two of 

 each type were transplanted to the experimental garden in May, 1905. Two 

 of the types included were apparently different from each other only in the 

 character that one of them bore flowers with broad petals resembling those of 

 lamarckiana, while the other was furnished with cruciate flowers, but with the 

 petals broader than the typical cruciata and quite as long as those of lamarck- 

 ^ana. It was evident that the two forms constituted an illustration of 

 Mendelian combinations, alike in all particulars except as to the characters 

 united in the form and size of the petals. 



One of the individuals with the broadly cruciate flowers bore a branch near 

 the base of the stem, on which were formed only flowers of the broadly-petaled 

 lamarckiana type. Some of these were purely fertilized and seeds preserved 

 for testing. These were duly sown in December, 1905, under glass, and 

 representative individuals brought to bloom in the open air in July, 1906. 



When they came into bloom in July, 1906, it was found that the branch- 

 sport came entirely true to the type which it represented. With this it is 

 interesting to note that the purely fertilized seeds of the main stem bearing 

 cruciate flowers gave a progeny which contained some individuals bearing 

 flowers with broad petals, while the other strain, which bore only broad 

 petals, came entirely true to its type without deviation. No exact numerical 

 count was made, but it seemed evident that the cruciate petal is dominant 

 over the cordate, and that the plants described above exemplify the develop- 

 ment of a sport on a plant of the first generation in which the recessive char- 

 acter appeared and when extracted came true to the recessive character. 



