THE ROOT. 19 



countries, especially in deep forests where the light is parti- 

 ally excluded, — it being unfavorable to their development, 

 A notable example is furnished by the Banyan^tree of 

 India, and some other Fig-trees, whose outstretched 

 branches send down adventitious roots, that grow into 

 the soil, and thus become supporting cdlumns. The 

 Screw-pine is sometimes wholly propped up by roots that 

 originate some distance from the ground. The, Sugar- 

 Cane produces aerial roots similar to those of Indian 

 Corn, but they develop from joints higher up. The seeds 

 of the Mangrove of the West Indies sprout before falling 

 from the tree, and send a long root, or radicle, down into 

 the mud, in which these trees grow, thus gaining a foot- 

 hold before severing their connection with the parent tree. 



13. Aerial roots, whose function is somewhat different 

 from the above, are found in epiphytes (Gr. epi, upon ; 

 pTiyton, plant), or air-plants. They generally grow on 

 other plants, as their name signifies, but their roots serve 

 merely to give the plant attachment, and the food is 

 derived wholly from the air. Many of the beautiful 

 Orchids of the Tropics are of this nature. The Epiden- 

 dron, or Tree Orchis (growing on a species of Magnolia), 

 and the Tillandsia, or Spanish Moss (hanging in tufts or 

 festoons from trees), of the Southern States, are epiphytes. 

 Many Mosses, Lichens, etc., are epiphytic, though destitute 

 of true roots. 



14. Certain plants not only fix themselves to, but also 

 draw their nourishment from, other plants. Such are 

 parasites. They send their roots, or what abswer func- 

 tionally to them, into the tissue of their host and absorb 

 the nourishment which the latter had prepared for its own 

 use. True parasites are destitute of the green substance in 



