PLANT SOGIETIMS 41] 



peculiar kinds of plants. He may not know the 

 plants, but he knows that they look different in the 

 different places. That is, the physiognomy of any 

 place is determined not alone by its physical fea- 

 tures, — as elevation, soil, rock, water, — but in large 

 part by its vegetation. 



519a. The plants of any region are known, collectively, as its 

 flora. Thus, we speak of the flora of America, or the flora of a 

 meadow. 



520. This means that plants live together in 

 communities, those which are suited to the same 

 physical environments and to each other being 

 driven together by the force of circumstances. 

 Local gardens have the same kind of weeds 

 salt marshes the same grasses and weeds, mill- 

 ponds the same herbs. Pigweeds do not grow 

 in woods, nor dandelions in marshes, nor skunk- 

 cabbage on lawns. There are, then, two things 

 to be considered in the plant societies, — the fact 

 that certain plants associate, and the fact that any 

 one plant is not equally distributed everywhere. 



521. Let the pupil observe any plant society 

 with which he often comes in contact, for the 

 purpose of determining what plants give it its 

 particular tone or character. The society may be 

 the flora of a familiar roadside or of a fence-row. 

 In some societies, he will find the physiognomy 

 to be the result of an approximately equal blend- 



