58. 



in the outer layers of the bark and have retained only 

 the fiinction of anchoring roots which hold the fern in 

 place and also aid in the accumulation of humus, The 

 question arises whether this fern is to he regarded 

 as a true epiphyte when such conditions are established. 

 In answering this question one may suggest a clas- 

 sification of epiphytes based upon that of Went though 

 somewhat modified. 



Epiphytes may be classified into Eu-epiphytes, 

 Hemi- epiphytes and Pseudo- epiphytes. 'As eu^-piphytes, or 

 true epiphytes, we may regard those plants only which 

 no longer derive their minearl elements or water from 

 the substratum to which they are attached, These epiphytes 

 have undergone some modification of their organs so 

 that they can obtain these substances from the air, The 

 attachment to the substratum is usually accomplished 

 by modified roots which function s%ely for anchoring 

 To this group belong many bromeliads and orchids, 

 Hemi epiphytes, or facultative epiphytes, are those 

 plants which although having lost connection with 

 the earth still derive water and other nutrient substances 

 from the substratum to which they are attached by 

 more or less modified soillroots which are imbedded in 

 the substratum.These epiphytes may occasionally occur 

 on the ground also, though tjieir most usual habit is one 



