The Mode of Inheritance of Semi-Sterility in the Offspring of Certain Hybrid Plants. 307 



good characters it aloue possesses. The Velvet bean was crossed by 

 Lyon pollen by R. Y. Winters, now of the North Carolina Experiment 

 Station, in 1908. I crossed the Lyon by the Velvet in 1910, the Vel- 

 vet by the Yokohama in 1911, and the Velvet by the China in 1912. 

 Every year the successive generations of these four crosses have'lTeen 

 raised on a large scale. The plants have to be grown eight feet apart, 

 so that mingling of the vines can be prevented, and a thousand plants 

 require nearly two acres, useful early forage plants have been raised 

 from among the segregates of the first cross. 



Fig. 2. Pod of Lyon bean. Natural size. 



(Many species and varieties of Stizolobiuiu liave been crossed by 

 Oliver in the greenhouse at AVashingtbn, D. C, and by Piper and Tracy 

 at Biloxi, llississippi.) 



In our breeding work the precautions necessary for scientific 

 pedigree cultures were of course followed. Some of these precautions 

 have been enumerated by Baur and by East. In our large plantings, 

 a copper label with the pedigree number went with every seed planted, 

 and all the notes made during the growing season referred to this label 

 which went into the sack when the crop was reaped. 



The countings and calculations in this paper have been done twice, 

 from the original detailed records. The state of the pollen in each 

 flower examined was separately recorded, as was that of every seed or 



22* 



