AQUATIC AND TERRESTRIAL PLANTS 



199 



alarias, or bladder -worts. In some waters, particularly 

 in the ocean, there are enormous quantities of free-swim- 

 ming microscopic life, both animal and vegetable, which 

 is carried about by currents : this is known under the 

 general name of plankton (Greek for "wandering" or 

 "roaming"). 



331. The general tendency has been for plants to 

 become terrestrial, or land -inhabiting. Terrestrial plants 



841 Sphagnum bog, green and living on top, bnl dead and dying anderneath. 

 Sphagnum ma d by nurserymen and Hi packing material (or plants. 



often grow in we\ places, bul never in water throughoul 

 their entire life; of sued are swamp, bog, and marsh 

 plants. Some plants have the ability to grow in standing 

 water wrhen young and to become terrestrial as the water 

 dries up. Such are amphibious. Some buttercups are 

 examples. 



332. Some plants grow in vers special soils or special 

 localities, and consequently are infrequenl or are confined 

 to certain well-marked geographical regions. Pig. 344. 

 Common plants art thost which an abU to accommotlatt 



