CHAPTER XIV 



REPRODUCTION 



THE production of new individuals by any method 

 whatsoever is reproduction in the broader sense. Physio- 

 logically it is a complex and peculiarly interesting pro- 

 cess. In the higher plants, - - angiosperms and gymno- 

 sperms, - - we are concerned with reproduction by seeds 

 and reproduction by vegetative parts. 



Seeds are embryonic plants with a certain food-supply 

 and protective coverings, while vegetative parts may be 

 shoots or any portion of the old individual which, when 

 placed under favorable conditions, will develop shoot and 

 root. The one type is usually sexual ; the other is invari- 

 ably nonsexual. 



Vegetative reproduction generally implies (1) the ad- 

 ventitious development of roots, as in cuttings, bulbs, 

 the potato, etc., where buds are preformed; or (2) of both 

 root and bud, as in the sweet-potato, Dahlia, etc. Repro- 

 duction by seeds involves commonly a variety of phe- 

 nomena including the differentiation of new structures, 

 the fusion of cells (gametes), and the origination of a new 

 individual from a fertilized egg-cell. 



202. The seed habit and vegetative reproduction. - 

 Reflection upon the general conditions prevailing among 

 cultivated and wild plants leads to the conclusion that the 



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