Phenology 



The study of the periodic phenomena of animal and 

 plant life and their relations to the weather and climate, 

 e. g. the time of flowering in plants, cf. Periodicity, Aspec- 

 tion. 



Phenotype 



The expression of the characteristics of an organism as 

 determined by the interaction of its genie constitution and 

 the environment, cf. Genotype, Ecad. 



Phloem 



The tissue in plants that conducts foods such as sugar 

 which is performed especially by the sieve tubes. 



Phoresy 



The transport of one organism by another, e. g., mites 

 carried by insects. 



Phosphorescence 



See Bioluminescence. 



Photeolic 



See Nyctinasty. 



Photic Zone 



The upper portion of bodies of water into which light 

 penetrates in sufficient intensity to influence plants or ani- 

 mals, cf. Aphotic zone. 



Photogenic 



Refers to the capacity of a substance to produce light, 

 cf. Bioluminescence. 



Photokinesis 



The undirected locomotion of many lower organisms in 

 response to light, accomplished by their capacity to influ- 

 ence the speed of their movements, cf. Phototaxis, Ortho- 

 kinesis. 



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