Tuber 



An enlarged, underground stem, tending to be oval or 

 spherical in shape, usually rich in starch, and capable of 

 vegetative reproduction of the plant, e.g., a potato tuber. 



Tufa 



A porous rock formed by the deposition of material, 

 especially calcium carbonate from water, as in springs, cf. 

 Travertine, Sinter. 



Tularemia 



A disease in rabbits, rodents, and man, caused by the 

 microorganism Pasteurella tularensis, which is transmitted 

 by insects. 



Tullgren Funnel 



A modification of the Berlese funnel (q. v.) for separating 

 Collembolons (q. v.), Mites, larvae, and other small organisms 

 from the soil. cf. Baerman funnel. 



Tundra 



The treeless land in arctic and alpine regions, varying 

 from bare area to various types of vegetation consisting of 

 grasses, sedges, forbs, dwarf shrubs, mosses, and lichens. 



Turbidity 



The condition of a body of water that contains suspended 

 material such as clay or silt particles, dead organisms or their 

 parts, or small living plants and animals. 



Turf 



The layer of low, dense grassland, comprising the above- 

 ground portions and the upper roots and rhizomes with at- 

 tached soil particles, cf. Sward, Sod. 



Turgid 



The condition of a cell or a tissue when it is swollen 

 with water causing Turgor pressure (q. v.). 



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