Turgor Pressure 



The actual pressure of the sap within a cell against the 

 cell wall resulting from the intake of water by Osmosis 



(q. v.). 



Turion 



A winter bud on some water plants that becomes de- 

 tached, overwinters, and under favorable conditions develops 

 into a new plant. 



Turnover 



(1) The mixing of layers of water in lakes in the spring 

 and autumn, cf. Thermal stratification. (2) The period of 

 time required for an organism to grow, mature, die, and 

 undergo decomposition. 



Tussock 



A plant-form that is tufted, bearing many stems arising as 

 a large, dense cluster from the crown, e.g., a large bunch 

 grass such as Arizona fescue. 



Twin Communities 



Communities that are similar in a dominant or com- 

 bining layers, or in Synusiae (q. v.), but vary in others. 



Tychocoen 



See Ubiquist. 



Type 



(1) A kind of vegetation, e.g., Community-type, forest 

 type, birch type. (2) The one or more specimens of a species, 

 subspecies, or variety on the basis of which the Taxon was 

 described. (3) One of the groups of soils in a soils series, 

 e.g., Miami silt loam type in the Miami series. 



Typhoon 



A Tropical cyclone or Hurricane (q. v.) in the Far East, 

 particularly in the China Seas. 



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