278 Principles of Plant Culture. 



443. The After-Care of Crosses. After the last pol- 

 lination, the blossom should again be inclosed until 

 fecundation is effected, which is indicated by a rapid 

 enlargement of the ovary. The paper sack may then 

 be replaced by one of mosquito netting. This should 

 be securely, but not too tightly, tied about the stem of 

 the pollinated flower, to protect the inclosed fruit or 

 seed-vessel from injury during growth and maturity, 

 as well as to render it conspicuous. A label should be 

 placed within the sack, or tied on with it, giving the 

 name of the variety whence the pollen was secured. It 

 is also desirable to record all the operations and ob- 

 servations relative to the crossing. 



444. The Selection of Crossed Seedlings is a most 

 important operation in producing new varieties by 

 crossing. If none of the seedlings of the first genera- 

 tion exhibit the desired qualities, those of a succeeding 

 generation may exhibit them. The plants nearest the 

 ideal should be selected, and all the seeds from these 

 preserved for planting. When the ideal plant is 

 found, it may be readily fixed by means of cuttings or 

 grafts in plants generally propagated in this way. In 

 those propagated by seed, several generations of cul- 

 ture and selection may be necessary before the progeny 

 will uniformly resemble the parent. 



The variations in the seedlings from two crossed 

 varieties, and the kind of selection needed to fix the de- 

 sired variations, are illustrated by the following dia- 

 gram (Fig. 173). Let a represent the seeds from two 

 crossed flowers A and B. The plants from these seeds 

 will probably be quite variable, as is indicated by the 



