Part IY. 

 REPRODUCTION. 



I^^TRODUCTION. 



In the process of reproduction germs^ or in other ^\'orcls foun- 

 dations for new individuals, are formed. Tliese germs usually 

 separate from the mother-plant when niature ; sometimes they re- 

 main united to the mother-jDlant for a shorter or longer time, or 

 even during the entire life-period. First case : The germs soon 

 become separated ; in this case they have special structural adapta- 

 tions for the purposes of protection, distribution, etc., and, above 

 all, special physiological properties. The most important repro- 

 ductive germs belonging here have specitic names : seeds {phan- 

 erogains)^ spores {cryptogams). Second case : The germs remain 

 in organic union with the mother-plant during the entire life- 

 period or only for a short time. («) In mosses this union exists 

 during the entire life-period of the plant, (i) In ferns the daugli- 

 ter-])lant is set free by the gradual decay and disappearance of the 

 mother-plant (prothallium). (c;-) In propagation by means of l)ulbs, 

 corms, runners, stolons, etc., the daughter- plant is made indepen- 

 dent by the gradual disappearance of that part which unites it to the 

 mother- plant. Daughter- and mother- plant may then exist side by 

 side independent of each other. 



Keproduction, or the formation of new plant-individuals, is 

 rarely limited to one method. In the same plant there are usually 

 two or more methods of reproduction. The difference consists 

 either (1) in that the germs are formed by different parts (organs) 

 of the mother-plant ; or (2) that one germ is formed sexually, the 

 other by one or several of the various asexual methods ; or (3) that 



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