HOW PLANTS ARE PROPAGATED 99 



fences to catch the " tumble weeds " (such as Russian 

 thistle) which roll before the wind scattering their seeds. 

 Those caught by the fences are burned. 



Some seeds travel by water, and may even cross the 

 ocean and spread the plant to new continents. 



Seeds keep best in a cool, dry place. Some lose the 

 power to grow in a short time, but most seeds live two 

 or three years, and some can live a very long time. 



How may seeds be tested? Seeds that we buy are 

 often so old that they do not grow well. They may also 

 be mixed with weed seeds. We may easily test them by 

 putting them on some wet cloth or blotting paper in a 

 soup plate, and covering them with another plate or 

 piece of glass. Put them where it is warm enough to 

 make them grow well. If eighty out of a hundred 

 seeds grow, we may say that eighty is the percentage of 

 germination. A simple test of this sort may save a 

 good deal of money when buying large quantities of 

 seed. 



OTHER WAYS OF PROPAGATING 



Why do we not always propagate plants by seeds? 



Some plants (such as apples and potatoes) do not give 

 just the same sort of plant when propagated by seed, 

 but do so when propagated by cuttings or by grafting. 

 The seeds of an early apple may give late apples or 

 winter apples, but scions or cuttings will produce a tree 

 like the one they come from. 



