Roots and Their Environment 



189 



Boston ivy, and truippet creeper, develop holdfast roots which 

 help to support the vines on trees, walls, and rocks. By 

 forcing their way into minute pores and crevices, they hold 

 the plant firmly in place. Usually the roots die at the end of 

 the first season, but in the trumpet creeper they are pereimial. 

 In the tropics some of the large climbing plants have holdfast 

 roots by which they attach themselves, and long, cordlike 

 roots that extend downward through the air vmtil they strike 

 the soil and become absorbent roots. 



Epiphytes. A plant that lives perched on another plant is 

 an epiphyte (Greek : epi, upon, and phyton, plant) . Mosses 

 and hchens are the most common epiphytes in temperate 

 regions, but in the rainy 

 tropics and along our own 

 Southern coast many flower- 

 ing plants live attached to the 

 branches of trees. They usu- 

 ally have leathery leaves and 

 a low transpiration rate. 

 Many have water-storage 

 tissue in fleshy stems or ia 

 thickened leaves. Others are 

 called tank epiphytes, because 

 they catch water in the axils of 

 the leaves or in pitcher-Hke 

 leaves. Epiphytes cling to 

 the supporting tree by means 

 of roots that act both as hold- 

 fasts and water-absorbing 



ml J i X 1 Fig. log. Elorida epiphyte (Tillanisia). 



organs. They do not take ^^ ^^,„^g^ ^^ ^^ b^^^^u^ ^^ p^^^^pp^^ 

 their nourishment from the family. 



