84 MORPHOLOGY OF ROOTS [LESSON 5. 



Pine-tree, but because it is like a Pine-apple plant) ; and the famous 

 Banyan of India, and some other Fig-trees, furnish the most remark- 

 able examples of roots, which strike from the stem or the branches 

 in the open air, and at length reach the ground, and bury them- 

 selves, when they act in the same manner as ordinary roots. 



80. Some of our own common plants, however, produce small 

 aerial rootlets ; not for absorbing nourishment, but for climbing. By 

 Ihese rootlets, that shoot out abundantly from the side of the stems 

 and branches, the Trumpet Creeper, the Ivy of Europe, and our 

 Poison Rhus, here called Poison Ivy, fasten themselves firmly 

 to walls, or the trunks of trees, often ascending to a great height. 

 Here roots serve the same purpose that tendrils do in the Grape- 

 Vine and Virginia Creeper. Another form, and the most aerial of 

 all roots, since they never reach the ground, are those of 



81. Epiphytes, OF Air-PlantS, These are called by the first name 

 (which means growing on plants), because they are generally found 

 upon the trunks and branches of trees ; not that they draw any 

 nourishment from them, for their roots merely adhere to the bark, 

 and they flourish just as well upon dead wood or any other con- 

 venient support. They are called air-plants because they really 

 live altogether upon what they get from the air, as they have no 

 connection with the soil. Hundreds of air-plants grow all around 

 us without attracting any attention, because they are small or hum- 

 ble. Such are the Lichens and Mosses that abound on the trunks 

 or boughs of trees, especially on the shaded side, and on old walls, 

 fences, or rocks, from which they obtain no nourishment. But this 

 name is commonly applied only to the larger, flower-bearing plants 

 which live in this way. These belong to warm and damp parts of 

 the world, where there is always plenty of moisture in the air. The 

 greater part belong to the Orchis family and to the Pine- Apple 

 family ; and among them are some of the handsomest flowers known. 

 We have two or three flowering air-plants in the Southern States, 

 though they are not showy ones. One of them is an Epidendrum 

 growing on the boughs of the Great-flowered Magnolia : another is 

 the Long-Moss, or Black Moss, so called, although it is no Moss 

 at all, which hangs from the branches of Oaks and Pines in all 

 the warm parts of the Southern States. (Fig 61 represents both 

 of these. The upper is the Epidendrum conopseum ; the lower, the 

 Black Moss, Tillandsia usneoides.) 



82. Parasitic Plants exhibit roots under yet another remarkable 



