^92 REPORTS OF INVESTIGATIONS AND PROJECTS. 



Variation in Wild Plants. — During the year about the same progress was 

 made in this work as reported in Year Book No. 7. Dr. Harris reports that 

 the results of considerable of the work are nearly ready for publication. 



Quantitative Investigations of Fertility and Fecundity in Plants. — The 

 fitness of an organism to survive in the struggle for existence is of evolution- 

 ary significance only if it is also capable of leaving a sufficient number of 

 descendants to give them an excess of weight in determining the character- 

 istics of succeeding generations. This must be admitted, whether one holds 

 that evolution is due to the accumulation of fluctuating variations or to muta- 

 tions. Thus studies of fertility and fecundity are of cardinal importance in 

 evolutionary investigations. 



For some years past Dr. Harris has been accumulating extensive series of 

 quantitative data on fertility in various wild and cultivated species. Some of 

 the problems under consideration are : 



The relationship between the degree of vegetative development and 

 fertility and fecundity. 



The correlation between the number of reproductive bodies formed and 

 the number which develop to a stage in which they may function in 

 propagation. 



The correlation between somatic characters and fertility. 



The relationship between symmetry in the fruit and fecundity. 



Fertility and fecundity of homologous material under different environ- 

 mental conditions. 



Some of the results of these studies will be ready for publication shortly. 



Investigations of Variation, Correlation, and Inheritance of Quantitative 

 Characters in Garden Beans. — Dr. Harris's chief attention, since coming to 

 the Station, has been given to quantitative investigation of variation, corre- 

 lation, and inheritance of the minute differences commonly described as 

 fluctuations, in several varieties of garden beans. The experiments are being 

 carried out on an extensive scale in various habitats at the Station for Ex- 

 perimental Evolution, in eastern Kansas, the Missouri Botanical Garden, and 

 southeastern Ohio. Some of the chief problems under consideration are: 



The factors influencing the size of the bean seed. 



A detailed investigation of the problem of pure-line inheritance, under 



various conditions and with several varieties. 

 The influence of the weight of the seed upon the characteristics of the 



plant developing from it. 

 The influence of environmental conditions upon the characteristics of 



individuals and their offspring. 

 The inheritance of fertility and fecundity. 



This year the cultures were cut down to the lowest point possible to permit 

 working up the large amount of material grown last year and to set time free 

 for the larger experiments planned for 1911. About 15,000 individually 

 recorded seeds were planted. 



