Arable (land) 



Land suitable for cultivation by plowing or tillage, does 

 not require clearing or other modification. 



Arachnid 



An animal in the class Arachnida which includes spiders, 

 mites, ticks, scorpions, and king-crabs. 



Arachnoid 



Refers to an Arachnid, particularly spiders or spider- 

 webs; cobwebby. 



Archaeophyte 



A weed introduced in prehistoric time into cultivated 

 ground. 



Archegonium 



The organ producing the egg in many groups of plants 

 such as mosses, ferns, and most Gymnosperms. 



Archibenthal 



Refers to the Archibenthic zone. 



Archibenthic Zone 



The layers of the ocean between depths of about 200 feet 

 and 3300 feet, the upper part of the Abyssal zone (q. v.). 



Arctic 



Refers to the regions in high latitudes from which tree 

 growth is usually absent because of the shortness of the grow- 

 ing season and other unfavorable environmental conditions; 

 may also be used as a noun for the region. 



Arctic-alpine 



Refers to the arctic and alpine regions jointly. 



Arctic Life Zone 



One of Merriam's life zones (q. v.), the portion of the 

 Boreal life zone (q. v.) north of the limits of tree growth, 



SO 



