30 University of California ruhUcations in Botany [Vol. 7 



to have borne sncli shoots duriug the season previous to coHcetion. 

 Diii'iiiir the present season (1916) only six rootstoeks produced such 

 normally flowering shoots ami 1lic i riiiaiiidri- pi'odueed shoots with 

 undeveloped flowers. Table 2 gives the history of twenty-three of the 

 rootstoeks in the garden cultures and imlndes three of the six normally 

 flowering plants of the 1016 season. The other three flowering plants 

 were fmin rootstoeks wlii--li have been under observation during two 

 seasons only. 



In table 2 characteristic eases were chosen, and a wide range of 

 original habitat of the rootstoeks was selected to emphasize the fact 

 that the production of undeveloped flowers is peculiar to all root- 

 stocks, irrespective of the soil or climatic conditions under which 

 they were originally growing. Further, the instances cited include 

 nearly all of the rootstoeks which produced normally flowering shoots 

 for more than a single season following collection. Rootstoeks 3, 31, 

 55, 57 and 88 exhibit the extreme condition in that when collected 

 they bore shoots with undeveloped flowers and have continued to 

 produce only such shoots thereafter. Rootstoeks 5, 69, 70 and 77 

 were collected with normally flowering shoots and the following year 

 and thereafter produced shoots with undeveloped flowers only. 

 Rootstoeks 1. 2. 7. 29 and 48 and rootstoeks 45. 71, 81. 83 and 

 93 continued to produce normally flowering plants for respec- 

 tively two and three years following collection and thereafter 

 have produced plants with undeveloped flowers only. There is, 

 then, no doubt that the change from perfectly normal flower 

 to undeveloped flower can take place in a single season and that 

 when this change has once taken place it may, in the majority of 

 cases, be expected to reappear in succeeding years more or less 

 indefinitely. These points have many times been confirmed by field 

 observation during the past six years. 



The histories of rootstoeks 4, 11 and 39 are obviously of importance 

 in this connection. Here we have cases in which rootstoeks have 

 produced only plants with undeveloped flowers for three successive 

 seasons or more and then in a single season have produced plants 

 with large, perfectly normal flowers. In the case of rootstock 4 the 

 flower produced was the first one ever seen from this rootstock, 

 which was originally collected on Point Reyes peninsula, and it is 

 interesting to note that this flower, produced after six years of growth 

 under different conditions of soil and climate, corresponds exactly in 

 color and other characters (cf. Goodspeed and Brandt, 1916) to 



