The Mode of Inheritance of Semi-Sterility in the Offspring of Certain Hybrid Plants. 315 



reasons given above. To obtain a more accurate count, a glass slide 

 was coated with albumin, and pollen from several flowers thinly spread 

 over it with the end of the finger. Tliis slide was covered with a 

 large cover-glass, and absolute alcohol gently put in. In due time this 

 was replaced by clove oil saturated with Orange G, and the specimen 

 kept at SO" C for several days, after whicli xylol and xylol balsam 



Fig. 7. A plant of the first generation of the Velvet by China cross, in flower. 

 Scale in feet. 



were put in. The plant physiologist of this Station, B. F. Floyd, 

 made counts of these grains. His totals, for 60 fields, were 1016 full 

 to 1097 empty grains, which is 52 per cent of empty grains. The 

 pollen from 103 flowers has been examined with the microscope, at 

 different stages in the flowering period of the plants, from the first to 

 the last flowers, with the same result. The drv full grains, observed 



