CHAP. XIII EPIPHYTES. PARASITES, SAPROPHYTES 69 



1. That the roots hang down into the air and do not seem 



to need to penetrate the earth. 



2. That the air of the greenhouse is damp and warm. 



3. That the leaves are expanded and green. 



4. Make a sketch of the Orchid to show these points. 



5. This is an epiphyte, or a plant which grows upon another 



plant and yet does not draw any nourishment from it. 



6. The roots are called aerial roots, and obtain nourishment 



from the damp air. The most conspicuous epiphytes 

 are found growing in the tropical zone. 



II. Take a Lichen, such as are common upon the bark of 

 trees. Notice : 



1. That it simply grows upon the surface. 



2. It is a good example of an epiphyte, but it belongs to an 



entirely different class of plants from those we have 

 been studying It has no distinct stem and leaves, 

 no flowers, no real roots, etc. (It belongs to those 

 plants which we call flowerless plants, while we are 

 studying the flowering plants chiefly.) 



III. Take a piece of Mistletoe, together with a portion 

 of the branch to which it is attached. Notice : 



1. The distinct stem. 



2. The expanded, green leaves. 



3. The close union with the host (i.e. with the tree or shrub 



upon which it is growing) . 



4. Make a sketch to show these characteristics. 



IV. Cut through the base of the Mistletoe and the branch 

 of its host at the point of union (longitudinally as regards 

 the mistletoe). Notice : 



i. The extension of the Mistletoe under the bark of the 

 host. 



