18 ELEMENTARY BOTANY. 



tufts or festoons from trees) of the Southern States, are epi- 

 phytes. 



10. Certain plants not only fix themselves to other plants, 

 but also draw their nourishment from them. Such are Para- 

 sites. They send their roots, or what corresponds function- 

 ally 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 leaves, 

 which is called chlorophyll. When this is present the plant 

 can in sunlight convert the inorganic matter into plant food. 



11. The Fungi (as Rusts, Smuts, Blights, Moulds, etc.) are 

 either parasitic on living plants or draw their nourishment 

 from decaying substances. The leafless Ouscuta, or Dodder, 

 is a slender yellow flower-bearing parasite of peculiar nature. 

 The seeds sprout in the ground, and the plantlet, as soon as 

 it appears above the surface, seeks for a support around which 

 to twine ; if unsuccessful it soon dies, but if it finds a proper 

 host-plant, it closely entwines the same producing suckers 

 by means of which it absorbs sufficient nourishment for its 

 growth and development. The lowest portion of the stem of 

 the parasite then dies, and thus severs its connection with the soil. 



12. The Mistletoe of Europe and the False Mistletoe of this 

 country have chlorophyll in their leaves, and are therefore 

 capable of converting inorganic into organic (vegetable) mat- 

 ter; that is, of preparing their own food. Yet they do this 

 only in part. They draw a portion of their food from the 

 trees on which they grow, and to that extent are parasitic. 

 The nature of the yellowish or whitish leafless plants, as 

 the Indian-pipe and Cancer-root, which are fixed to the 

 ground, should not be misunderstood. They do not draw 

 their nourishment from the soil, but from underground roots 

 on which they are parasitic. Neither should all subterranean 

 parts of plants be regarded as roots, since stems sometimes 

 grow underground. Stems, however, are easily recognized by 

 the buds and scales (modified leaves) which they produce, 

 and by the presence of a pith which may be seen by examin- 

 ing a transverse section ; in roots no pith is formed. 



