THE FRUIT AND THE SEED 103 



by it. In nature, seeds of the latter class are usually 

 dropped from the parent plant before becoming dry 

 and are soon covered by leaves or other litter that keeps 

 them moist. Nurserymen either plant such seeds as soon 

 as they are ripe, or if of species that do not germinate as 

 soon as ripe, they imitate nature. 



169. Stratification of seeds. This is a process de- 

 signed to give natural conditions to the mature seed. It 

 consists in mixing the freshly-gathered seeds with sand, 

 taking care that the sand is kept moist until the time for 

 sowing arrives. Large quantities of seeds may be stratified 

 in boxes, by placing the moist sand and seeds in alternate 

 layers, or the layers may be built up in a pile on the ground. 

 The sand should be coarse enough to admit some passage 

 of air between the particles and to give perfect drainage. 

 The layers should not much exceed an inch in thickness, 

 except for the larger seeds, and the number of layers should 

 not be so large as to prevent proper aeration of the mass. 

 Small quantities of seeds may be mixed with sand or 

 porous loam in flower-pots. Moisture may be maintained 

 in the boxes or pots by burying them a foot or more deep 

 in the soil in a well-drained place, or by storing them in a 

 moist cellar. Care is necessary to keep mice and other 

 vermin from stratified seeds. It is well to cover pots in 

 which valuable seeds are stratified, with a sheet of tin or 

 zinc ; metal labels are best for distinguishing different 

 sorts of seed. The seeds should remain stratified until 

 sowing time, when they may be sifted out ol the sand or 

 sown with it, as is more convenient. Seeds that do not 

 germinate well until the second spring after maturity 

 (162) are commonly left in stratification until that time. 



