F Layer (Soil) 



Sometimes used to designate the partially decomposed 

 litter which can still be recognized as to origin and age. 

 cf. A horizon, H layer, L layer. 



Flocculation 



The aggregation of suspended colloidal material or very 

 fine particles into larger masses or floccules. 



Flood Plain 



The nearly level land forming the bottom of a valley 

 in which a stream is present and usually subject to flooding, 

 cf. First flood plain. 



Floodway 



A channel usually bordered by levees for the purpose 

 of carrying flood water. 



Flora 



The sum total of the kinds of plants in an area at one 

 time. cf. Vegetation, Fauna. 



Floral Region 



See Floristic region. 



Floret 



The small flower of grasses or Composites. 



Florigen 



A hormone evidently made in the leaves which after 

 translocation to apical Meristem initiates the formation of 

 flowers. 



Floristic Area 



An area in which a certain degree of homogeneity exists 

 because of similarities in the areas occupied by various 

 species. 



145 



