132 TEE NATURE AND WORK OF PLANTS 



tinct. There are three principal methods by which 

 new individuals may be formed : vegetative repro- 

 duction by means of cuttings, buds, branches, etc., 

 simple or asexual spores, and egg formation. 



180. Reproduction by cuttings. — Select a good 

 healthy leaf of a begonia, cut it from the stem, 

 trim away nearly half of it, and put the raw edge 

 in sand kept moist in a shallow dish or box. Ex- 

 amine every week for a month. Roots will first be 

 formed, and then if the experiment is allowed to 

 run long enough a stem will appear, which will in 

 turn bear leaves like the original from which the 

 cutting was made. It is seen that the begonia is 

 able to replace the entire plant from part of a leaf 

 — a capacity that is shared by an extremely large 

 number of species. 



181. The stem may reproduce the entire plant. — 

 Cut a small twig of the willow, a stem of the ge- 

 ranium, coleus, or begonia, and insert in moist sand 

 as above. A few weeks later the cutting will be 

 found to have replaced the missing roots and leaves 

 and made a complete plant. 



182. The root may reproduce the plant. — Cut off 

 a portion of the fleshy root of a sweet potato or 



