256 Principles of Plant Culture. 
brush, and carefully applying it to the stigma. A pin, of 
which the head has been flattened by hammering, inserted 
in the end of a stick, forms a convenient tool for this work. 
The best time for pollination, in the open air, is often in 
the early morning, since the atmosphere is then usually still, 
and contains little pollen from other flowers, which, if freely 
present in the air, is liable to vitiate the results of our pol- 
lination. 
443. The After Care of Crosses. After the last pol- 
lination, the blossom should be again inclosed until fecun- 
dation 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 pro- 
tect 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 se- 
cured. It is desirable, also, to keep a notebook, in which 
all the operations and observations relative to the crossing 
are recorded. 
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 generation exhibit the 
desired qualities, the attempt need not be regarded as a 
failure, since 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. But in those propagated by seed, several generations 
