Phytometer 



A plant such as the sunflower, used to measure environ- 

 mental conditions. 



Phytopathology 



The study of plant diseases. 



Phytophagous 



See Herbivorous. 



Phytoplankton 



The plants occurring in Plankton (q. v.), e. g. diatoms. 



Phytosociology 



See Plant sociology. 



Phytotron 



An extensive set of rooms used for growing plants under 

 controlled environmental conditions. 



Pioneer 



A plant, animal, or community that first invades a bare 

 area, e. g., willows on a newly formed sandbar. 



Pisciculture 



The growing of fish. 



Pistil 



See Carpel 



Pistillate 



Refers to the pistil, e. g. pistillate flower. 



Pitting 



The making of shallow pits or depressions, especially in 

 rangeland, with an offset disk or pitting machine, in order 

 to retain rain water or snowmelt. 



Pituitary 



The gland inside the skull of vertebrates which is of 



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