520 CANNON: STUDIES IN PLANT Hyprips: 
have observed also that the peas used in the present study were 
fertile; they produced pods which were usually well filled with 
seeds capable of germination. These observations are in harmony 
with the manner of the formation of the spores; no irregularities 
whatever, which in any way were traceable to the plants as hybrid 
organisms, were seen. If these observations are correct, the con- 
clusion can hardly be avoided that the variations and reversions of 
hybrid peas are associated with normal processes, such as are found 
in the pure types, and hence that abnormalities are merely indica- 
tions of the hybrid nature of the forms that bear them, although 
by no means diagnostic characters. It is then a question fairly 
open for the cytologist to determine, what the nature of those 
processes are, and this has yet to be done. 
The hybrids used in this study, * Fillbasket x Debarbieux and 
Express x Serpette, showed variation after the law of Mendel, 
although I should state that they were not examined more than was 
necessary to surely establish this point. The seeds from which 
the plants studied were derived were from those of the first gen- 
eration. The Fillbasket x Debarbieux seeds were yellow and 
green, nearly in the ratio 3:1. Of course most of the flower-buds 
were removed for study, but in a few cases I left the flowers to 
fertilize themselves. The plants which came from the green seeds 
bore green seeds only, and those from the yellow seeds bore seeds 
that were both yellow and green in the ratio 3:1. In the crosses 
in which Serpette was used as one of the parents, as for example 
Express x Serpette, the Serpette dwarf character was noticed in 
the offspring as presumably the recessive one; it appeared in at 
least one third to one half the total number of third-generation 
plants. In Express x Serpette there were seventy-two plants 
which resembled the Express ancestor, and thirty which were 
dwarfed and which were like the Serpette race. The illustrations 
(f. 34-37) show fairly well the appearance of these reversionary 
types and the pure forms also. 
were raised. Professor Bateson very generously sent me some first crosses, several of 
the second generation and also the pure types. 
I wish also to acknowledge the assistance of Mr. Homer D. House, of Colum- 
bia University, for aid in preparing material for study, and that of Miss Palmyre de C. 
Clarke, of the New York Botanical Garden, who prepared the bibliography. 
