222 Atkinson. 



progression in the size of the flower has not been determined. It is not 

 accompanied by increased size of other members of the plant body. 

 Possibly it may bear some correlation to the self sterility, since certain 

 forms of sterility in plants are sometimes accompanied by more showy 

 flowers. It is known also that some hybrids are larger than either 

 parent, but the increase in size here relates only to parts of the flower. 

 The stigma does not overtop the stamens as in many of the large 

 flowered open pollinated Oenotheras. 



Another striking modification in hyhrida nutella is the lax in- 

 florescence and the consequent lax relation of the pods. This is a char- 

 acteristic of the annual as well as of the biennial forms. 



While hyhrida pycnella matures early, the annual forms very early, 

 hyhrida nutella matures late. The annual forms of nutella, even though 

 they flower early, continue to flower until killed by frost in November. 

 It would seem therefore that the earliness of nutans is not only in- 

 herited by pycnella, but also that a progression in this quality has 

 taken place so that the earliness of maturity is intensified. On the 

 other hand, the lateness of pyenocarpa is inherited by nutella and there 

 appears to have occurred a progression of the quality of lateness in 

 this hybrid. 



In hyhrida tortuosa the edge character of the stem leaves is pe- 

 culiar, the basal half having fewer teeth than either parent, over the 

 same extent, but the teeth are the size, but not the shape of those of 

 pyenocarpa. Tortuosa is the only one of the hybrids thus far which is 

 fasciated, all of the individuals except one presenting this character in 

 a marked degree, so that the over top of the main stem is not what 

 it otherwise would be. Tortuosa also continues to flower longer than 

 nutans, this character as well as that of fasciation probably being 

 drawn from pyenocarpa. 



Difference in habit between annual and biennial forms. 

 The habit of the annual forms of the two hybrids, pycnella and nutella, 

 is shown by my cultures thus far to be quite different. The plants are 

 lower in stature, and this is true of annual forms of pyenocarpa and 

 nutayis. The lower branches are more spreading, especially those arising 

 in the axils of the rosette leaves, but to some extent also, the lower 

 stem branches. The wider sprfeading branches wdth the lower stature 

 gives to the plant quite a different habit from that of the biennial 

 forms. This variation in form must be taken into account in any com- 

 parison of the hybrids with their parents. The habit varies also accord- 



