PHYSIOLOGY OF THE DEVELOPMENT OF PLANTS 411 



two has been proved by numerous experiments. The life of 

 many plants may be considerably prolonged by removing their 

 floral buds and thus preventing fruiting. By this method it is 

 possible, for instance, as has been done by Molisch, to make an 





Fig. 128. Fig. 129. 



Fig. 128. — Stages in development of the wild carrot, a biennial plant. On the 

 left the seedling; in center, plant at the end of first growing season, having formed 

 a fleshy root. On the right, a mature and blooming specimen in the middle of the 

 second year (after Transeau) . 



Fig. 129. — Century plant {Agave) showing rosette of fleshy leaves and flower- 

 ing stalk {after Transeau) . 



ordinary garden mignonette hve 2 or 3 years instead of 1 year. 

 It will then acquire the form of a small shrub. On the other 

 hand, when biennial plants, for some reason or other, produce 

 seeds during the first year— the so-called ''shooting to seed" in 

 beets and other root crops— then their vegetative organs will die 

 promptly. 



