Feral 



Refers to an organism that has escaped from cultivation 

 or domestication and become wild again. 



Fermentation 



The chemical alteration of organic substances by organ- 

 isms, especially yeast and bacteria, e.g., alcoholic fermentation 

 in which sugar is changed to alcohol and carbon dioxide by 

 the enzyme zymase, produced by yeast. 



Fertile 



Refers to the capability of an organism or organ such as 

 a stamen, pistil, or ovary to carry on reproductive functions. 



Fertility 



(1) The capability of an organism to produce living off- 

 spring, cf. Fecundity. (2) The quality of a soil which enables 

 it to provide substances in adequate amounts properly bal- 

 anced and available for the growth of specified plants when 

 other environmental factors are favorable. 



Fertilization 



The union of egg and sperm, or of two Gametes (q. v.). 



Fertilizer 



Any material added to soil to supply one or more plant 

 nutrients, usually not including lime or gypsum. 



Fibrous Root System 



The aggregate of the numerous, similar roots arising from 

 the base of the stem such as occurs in corn and the grasses. 

 cf. Tap root system. 



Fidelity 



The degree of regularity or "faithfulness" that a species 

 occurs in certain plant communities, expressed in a 5-part 

 scale: (5) Exclusive, (4) Selective, (3) Preferential, (2) Com- 

 panion, indifferent, (1) Accidental, strangers (q. v.). 



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