CHAPTER XXVII 

 REPRODUCTION IN PLANTS 



Sexual and Asexual Reproduction. — In the preced- 

 ing chapter it has been shown that animals have two 

 types of reproduction — sexual and asexual. Plants also 

 exhibit both types. It is proper at this point to re-empha- 

 size the fact that while both methods secure the perpetu- 

 ation of the race and may also serve to multiply it, one of 

 them — the asexual — merely reproduces the individual 

 without essential change, but that the other — the sexual 



— not only produces a new individual but also endows it 

 with characters from both parents. In this way it may 

 and usually does happen that the new individual is not 

 exactly like either parent. 



Types of Reproduction in Plants. — Since plants ex- 

 hibit a far greater variety in the details of reproduction 

 than animals it follows that no one example will suffice 

 to give an adequate picture. Moreover, although our 

 chief interest is with Seed Plants, it is quite impossible 

 to understand the significance of their reproductive proc- 

 esses without some knowledge of the evolutionary states 

 through which they have passed and which are still ex- 

 hibited by the lower orders of plants. For this reason 

 this chapter will deal in order of development with the 

 following five types of reproduction : (a) By resting spores 

 and swimming spores among the lowest plants — -^Mga; 

 and Fungi; (b) By simple types of sex cells — or gametes 



— in the same lower plants; (c) By alternation of a 

 sexual and an asexual generation — in Mosses and Ferns; 

 (d) By seeds in the higher plants; and (e) By various 

 sorts of purely vegetative division of plants, such as 

 bulbs, cuttings, grafts, buds, etc. 



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