The tobacco plant is naturally self-fertile, but cross- 

 fertilization is often effected among the plants by many 

 species of bees and insects, which carrv pollen from flower 

 to flower. This condition results in a large proportion 

 of the crop being hybrid plants in the following year, 

 and leads to great variability. In some species of plants 

 cross-fertilization is absolutely essential to seed produc- 

 tion. In other species it produces more and better seeds 

 than self-fertilization. But tobacco belongs to still 

 another class of plants which are abundantly self-fertile, 

 and in which self-fertilization has been proved by experi- 

 ment to be more effective for seed production than cross- 

 fertilization. 



The United States Department of Agriculture resort 

 to bagging the flower-heads of the selected plants to 

 prevent cross-fertilization, and thus to secure uniformity 

 among the leaves. The characters which are given the 

 closest attention in selecting the seed-plants are the 

 general habit of growth or type of plant : — the number, 

 shape, size, and uniformity of leaves, the distance be- 

 tween the leaves, time and uniformity of ripening, height 

 of plants, number of suckers, uniformity of colour of 

 leaves, and freedom from diseases. It is of vital im- 

 portance to select plants with a large number of market- 

 able leaves, in order to secure an increased yield. The 

 plants on which the lower leaves are over-ripe before 

 those near the top begin to mature should be discarded. 

 Seeds from plants shewing a few suckers will produce 

 a small number of suckers the following year, and those 

 shewing a large number will transmit this undesirable 

 tendency to the progeny, provided other things are equal. 

 After the selection of seed-plants has been made in the 

 field, the (lowering part of the plant is covered with an 



