VEGETATIVE REPRODUCTION 209 



and planted in soil, will commonly give rise 

 to new plants, and this faculty is taken 

 advantage of in propagating new and valuable 

 species. 



Sometimes young plantlets are produced 

 by the development of a cluster of cells which 

 still remains attached to the parent plant. 

 This happens in many ferns, where bulbils 

 are formed on the leaves or leaf stalks, and 

 when they are set free they are already 

 provided with all the organs necessary to 

 start at once into growth. The process of 

 propagation by gemmae and by young plantlets 

 is essentially the same, the difference consists 

 in the particular stage of development which 

 is reached when the propagative body is cast 

 adrift from the parent. The gemma is shed 

 at an early stage, while the bulbil represents 

 a gemma that has remained to develop on the 

 parent plant, and has been fed at its expense 

 during the early stages of growth. But there 

 are advantages and disadvantages in both 

 methods. The gemmae are small, and are 

 more readily dispersed over wide distances 

 than the larger young plants. Furthermore, 

 the latter by their very complexity are more 

 liable to perish unless they speedily reach a 

 spot in which they find conditions suitable 

 for immediate development. 



But in spite of these numerous and elaborate 

 kinds of vegetative reproduction, most plants 

 still retain the primitive capacity of merely 

 regenerating lost parts to a surprising extent, 



