208 WHERE PLANTS GROW 



in standing water when young and to become terrestrial 

 as the water dries up. Such are amphibious. Some 

 buttercups are examples; mermaid-weed (Proserpinaca) is 

 another. 



360. Some plants grow in very special soils or special 

 localities, and consequently are infrequent or are confined 

 to certain well-marked geographical regions. (Fig. 371.) 



374. Sphagnum bog, green and living on top, but dead and dying underneath. 

 Sphagnum moss is used by nurserymen and florists as packing material for plants. 



Common plants are those that are able to accommodate 

 themselves to widely different environments. Weeds are 

 examples. Many plants have become so specialized in habitat 

 as to be parasitic, saprophytic or epiphytic. (Chap. XV.) 



361. Common plants often grow in most unusual and 

 difficult places. Note that some weeds grow not only in 

 fields, but often gain a foothold in chinks in logs, on rot- 

 ting posts, in crotches of trees, on old straw stacks, in clefts 

 and crannies of rocks. In moist climates, as in England, 

 plants often grow on thatched roofs. 



362. Plants may be said to be seeking new places in 



