Pennsylvania!! 



A geologic period in the latter part of the Paleozoic era 

 which began about 255 million years ago and lasted for about 

 25 million years. 



Perched Water 



The body of free ground water in a zone of saturation, 

 separated from an underlying body of ground water by an 

 unsaturated layer of material. 



Percolation 



The downward movement of water in the soil, especially 

 in saturated or nearly saturated soil, cf . Infiltration. 



Perennate 



The continuance of life in an organism from year to year 

 as in a Rhizome or seed. 



Perennial 



A plant that lives for three or more years, cf. Annual, 



Biennial. 



Perfect 



Refers to flowers containing one or more stamens and 

 pistils. 



Perianth 



The flower parts surrounding the stamens and petals; the 

 petals and/or sepals of a flower; much reduced in some 

 flowers. 



Periodicity 



The repeated occurrence of events at fairly frequent and 

 regular intervals, cf. Aspection, Phenology. 



Periphyton 



The assemblage of organisms attached to surfaces sub- 

 merged in water, above the bottom, cf. Benthos, Plankton. 



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