XIV. REPRODUCTION 



394. Origin of Hew Individuals. The primal purpose of every 

 individual is to give rise to others, thus ensuring the continuation 

 of the species. The differentiation, and separation of masses of 

 protoplasm from the body, which undergo rejuvenescence, and 

 then pass through the chief stages in the development of a 

 typical individual of the same, or alternate generation, constitutes 

 reproduction. 



New individuals may arise by two general methods, according 

 to the character and origin of the protoplasm from which they 

 develop, which may be distinguished as monogenetic, vegetative 

 or asexual, and digenetic, or sexual methods of reproduction. 



Vegetative reproduction is that method by which a single mass 

 of protoplasm consisting of one or more cells ia cut off from the 

 parent and produces a new individual. This method gives rise 

 to a series of individuals perpetuating the qualities of a single 

 line of ancestors, which may become more or less fixed and ac- 

 centuated in successive generations. Vegetative reproduction is 

 carried on by plants of nearly all of the families in the vegetable 

 kingdom, and is the only method known in some forms. 



Two kinds of vegetative reproduction may be distinguished, 

 according to the nature of the special bodies concerned : somatic 

 propagation, budding or gemmation, and spore reproduction. In 

 somatic reproduction a mass of cells is cut off from the parent 

 and undergoes development into a new individual. A wide 

 variation is shown however. Gemmae may consist of but one 

 cell in some species, while in others the reproductive body is one 

 of the organs of the plant, but little differentiated from its vege- 

 tative form. Spores are generally single protoplasts of specialized 

 origin capable of giving rise to a new individual, and in this con- 



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