Allelomimetic Behaviour 



Two or more animals, mutually stimulated, acting sim- 

 ilarly. See Mimetic. 



Allelomorph 



See Allele. 



Allelopathy 



Influence of plants, exclusive of microorganisms, upon 

 each other, caused by products of metabolism. 



Allen's Principle (Rule) 



Appendages of animals tend to be shorter in cold regions, 

 resulting in reduced loss of heat. Cf. Bergmann's, principle. 



Allergen 



A substance which induces allergy, or causes symptoms to 

 show, e.g., Pollen. 



Allergy 



Sensitivity resulting in pathologic condition in certain 

 people to substances such as pollen, food, hairs; or may be 

 caused by mental or environmental conditions. 



Alliance 



A group of plant associations according to Braun- 

 Blanquet classified together on the basis of similarity in 

 floristic and sociological characteristics. See Association. 



Allochoric 



Refers to a species occurring in two or more similar 

 communities in the same region. 



Allochthonous 



Refers to deposits of material that originated elsewhere, 

 e.g., drifted plant materials on the bottom of a lake. cf. 

 Autochthonous. 



Allogamy 



Cross-fertilization (q. v.). See Outbreeding. 



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