environmental gradients; the distribution of natural com- 

 munities in an Ecocline (q. v.). 



Coenocyte 



A group of protoplasmic units; a structure with many 

 nuclei and no cross walls as occurs in a number of algae and 

 fungi. 



Coenospecies 



A group of Species in which hybridization is possible, cf. 

 Superspecies, Syngameon. 



Coffer-dam 



A barrier constructed in a body of water so as to form 

 an enclosure from which the water is pumped, to permit free 

 access to the area within. 



Cogonal 



An artificial Savanna of cogongrass (Imperata spp.) in the 

 Philippines. 



Col 



A high pass in a mountain range. 



Colchicine 



An alkaloid that inhibits Mitosis, obtained from the 

 autumn crocus (Colchicum autumnale), used to produce 

 polyploidy artificially. 



Cold-air Drainage 



The settling of cold air in low places displacing the 

 less dense warm air, as at the mouth of a mountain canyon. 



Cold Desert 



Land covered with snow and ice. 



Cold Front 



The boundary of a mass of cold air and a mass of warm 

 air. 



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