G Horizon 



A soil layer developed wholly or partly in Gley (q. v.) soil, 

 characterized by the presence of ferrous iron and usually by 

 neutral gray colors. 



Gigantism (Giantism) 



A plant showing excessive vegetative growth. 



Gilgai 



The type of microrelief characterized by a succession of 

 micro-basins and micro-knolls or many small ridges in nearly 

 level areas on clay soil having high coefficients of expansion 

 and contraction with changes in moisture content; "pits- 

 and-mounds." 



Girdling 



The removal of a ring of bark or tissues from a stem, 

 causing the death of the plant. 



Glacial Drift 



See Drift. 



Glaciation 



The covering of an area by a glacier or by an ice-sheet, 

 or the geological action of the glacial ice upon the land. 



Gleization 



The soil-forming process in which Gley soil is formed. 



Gley (Glei) Soil 



A soil formed under the influence of water-logging and 

 lack of oxygen; usually neutral gray in color and containing 

 reddish brown deposits of ferrous hydroxide, cf. G horizon. 



Gloger's Rule 



The generalization which states that animals in warm 

 climates tend to be darker in color than those in arid or cool 

 regions. 



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