EPIPHYTES AND PARASITES. 123 



EPIPHYTIC AND PARASITIC PLANTS. 



251. Some plants grow without any attachment to the soil, and are 

 able to derive in a great measure, from the atmosphere, all the ma- 

 terials required for their growth. Such plants are called Epiphytes (gV/, 

 upon, and QVTM, a plant), or air-plants, and may be illustrated by the 

 Tillandsias, Bromelias, and Orchids of warm climates. Such plants, 

 when attached to the surface of trees, may perhaps derive some nourish- 

 ment from the inorganic matter in the decaying bark; but they do not 

 become incorporated, so to speak, with the trees. 



252. There are other plants, however, which are true Parasites (KU.^K., 

 beside, and airo;, food, deriving food from another), sending prolonga- 

 tions of their tissue into other plants, and preying upon them. Many 

 Fungi, for instance, develop their spores (seeds) and spawn (mycelium) 

 in the interior of living or dead plants, and thus cause rapid decay. 

 The disease of corn, called smut and rust, and the dry rot in wood, are 

 due to the attacks of these parasitic Fungi. The minute dust or powder 

 produced by these plants, consists of millions of germs which are easily 

 carried about in the atmosphere, ready to fix themselves on any plants 

 where they can find a nidus. There are also flowering plants which 

 grow parasitically, and they may be divided into two classes; 1. Those 

 which are of a pale or brownish colour, and have scales in place of 

 leaves ; and 2. Those which are of a green colour, and have leaves. 

 The former, including Orobanche or broom-rapes, Lathra?a or tooth- 

 wort, Cuscuta or dodder, derive their nourishment entirely from the 

 plant to which they are united, and seem to have little power of elabor- 

 ating a peculiar sap ; while the latter, as Loranthus, Viscum or misle- 

 toe, Myzodendron, Thesium, Euphrasia, Melampyrum, and Buchnera, 

 expose the sap to the action of air and light in their leaves, and thus 

 allow certain changes to take place in it. The Misletoe, from its power 

 of elaboration, is able to grow on different species of plants, as on the 

 apple, beech, oak, &c. Some of these parasites are attached to the roots 

 of plants by means of suckers, as in the case of Broom-rapes, Tooth- 

 wort, and Thesium ; while others, as Dodder, Misletoe, &c., feed upon 

 the stems. The plants to which the parasites are attached give origin 

 frequently to their specific names. The species of Cuscuta or dodder, 

 inhabit all the temperate and warm parts of the globe, and are peculiarly 

 destructive to clover and lint. They are produced from seed which at 

 first germinates in the soil like other plants ; but after the stem has coiled 

 closely round another plant, and becomes attached to it by means of 

 suckers, then ah 1 connection with the soil ceases, and the Dodder con- 

 tinues its life as a parasite. A remarkable tribe of parasites, called 

 Raffiesias, has been found in Sumatra and Java. They are leafless, and 

 produce brown- coloured flowers, which are sometimes three feet in 

 diameter. On account of their only producing a flower and root, 

 they are denominated Rhizanths (*, a root, and v0o;, a flower). 



