Acclimation 



The increased tolerance or physiological adjustment of an 

 organism to a change in its environment. 



Accommodation 



Modification of the focus of the eye. 



Accrescent 



Refers to plants which continue to grow after flowering. 



Accumulator Plant 



A plant that absorbs certain elements which accumulate 

 in its tissues to a much higher degree than in most plants, 

 e.g., Equisetum concentrates large amounts of silica, cf. 

 Seleniferous. 



Acheb 



A short-lived type of vegetation, characterized chiefly 

 by mustards and grasses, in the Italian Sahara. 



Achene 



A one-seeded, dry, non-opening fruit in which the seed 

 is not attached to the wall of the fruit, e.g., sunflower 

 "seed." 



Aciculignosa 



Coniferous vegetation with small, evergreen, needle-like 

 leaves. 



Acid Bog 



See Bog. 



Acidophilous 



Refers to organisms that grow well or exclusively on soil 

 or in a medium that is acid in reaction. 



Acid Soil 



A soil with an acid reaction, containing more hydrogen 

 than hydroxyl ions; for practical purposes with a pH below 

 6.6. 



