Phreatophyte 



A plant that absorbs its water from a permanent supply 

 in the ground, e. g., willows along a stream. 



Phycology 



See Algology. 



Phylad 



A phylogenetic group of closely related species. 



Phylloclade 



See Cladophyll. 



Phylogeny 



The evolutionary development and relationships of a 

 group of organisms such as rodents or species of rose. cf. 

 Ontogeny. 



Phylum 



One of the major subdivisions used in classifying plants 

 and animals, e. g., Tracheophyta (vascular plants), Arthro- 

 poda (arthropods). 



Physiognomic Dominance 



Dominance (ecologic) (q. v.) caused by the similarity of 

 a number of species in a certain life-form rather than be- 

 cause of greater cover, number, or size of one or a few 

 species, e. g., a weed patch consisting of many species of 

 annual weeds similar in form. 



Physiognomy 



The appearance of vegetation as determined by the life- 

 form of the dominant plants, e. g., a grassland, pine forest. 



Physiographic Climax 



See Climax. 



Physiography 



The branch of physical science that deals with the physi- 

 cal features of the earth, cf. Geomorphology. 



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