PI.AXT SOCIETIES 



I I 



called colonies. Colonies of most plants are transient : 

 after a short time other plants gain a foothold amongst 

 them, and an intermingled society is the outcome. Marked 

 exceptions to this are grass colonies and forest colonies, in 

 which one kind of plant may hold its own for years and 

 centuries. 



In a large newly cleared area, plants usually first estab- 

 lish themselves in dense colonies. Note the great patches 



Fig. 9. — A Mid-region Society. 



of nettles, jewel-weeds, smart-weeds, clot-burs, fire-weeds 

 in recently cleared but neglected swales, also the fire-weeds 

 in recently burned areas, the rank weeds in the neglected 

 garden, and the ragweeds and May-weeds along the re- 

 cently worked highway. The competition amongst them- 

 selves and with their neighbors finally breaks up the 

 colonies, and a mixed and intermingled flora is generally 

 the result. 



In many parts of the world the general tendency of neg- 

 lected areas is to run into forest. All plants rush for the 



