AQUATIC AND TERRESTRIAL PLANTS 



199 



ularias, 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 



317. 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. 



often grow in wet places, but never in water throughout 

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

 plants. Some plants have the ability to grow in standing 

 water when young and to become terrestrial as the water 

 dries up. Such are amphibious. Some buttercups are 

 examples. 



332. Some plants grow in very special soils or special 

 localities, and consequently are infrequent or are confined 

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

 Common plants are those which are able to accommodate 



