Aphh 



A plant louse, an insect in the family Aphides, feeds by 

 sucking juices of plants, e.g., green-peach aphid (Myzus per- 

 sicae) which transmits more than 50 different plant viruses. 



Aphotic Zone 



The deeper portions of bodies of water to which daylight 

 does not penetrate with sufficient intensity to influence or- 

 ganisms, cf. Disphotic, Euphotic, Photic zones. 



Aphototropism 



The response of an organism by which it turns away from 

 the source of light, cf. Phototropic. 



Aphyllous 



Refers to plants lacking leaves. 



Aphytal Zone 



The part of a lake floor that lacks plants, includes the 

 sublittoral and profundal zones. 



Apocarpous 



Refers to flowers in which the carpels (q. v.) are not 

 joined together, e.g. buttercup flowers. 



Apogamy 



The reproduction of an organism without Fertilization 

 (q. v.). cf. Apomixis, Parthenocarpy. 



Apogeotropism 



The response of an organism by turning away from the 

 earth, cf. Geotropism. 



Apomict Population 



A population of organisms produced asexually. 



Apomixis 



Asexual reproduction of organisms in contrast to Amphi- 

 mixis (q. v.). It includes Vegetative propagation (q. v.) and 



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