128 GROWTH AND WORK OF PLANTS 



intimate connection with those of the host. Through these 

 haustoria the dodder absorbs solutions of mineral substances, 

 and also of carbohydrates and proteids manufactured by its 

 host. Receiving these food substances already prepared the 

 parasite has no need of chlorophyll nor of expanded leaves. In 

 accordance with the general law, therefore, that when an organ 

 ceases to function it becomes reduced or discarded, the leaves of 

 the dodder have become reduced to mere scales on the stem, and 

 the root dies as soon as the vine becomes attached to its host by 

 the haustoria. The vine and its scale leaves are pale yellowish in 

 color. The seeds of the dodder germinate in the soil developing 

 a true root and a slender vine which lives an independent exist- 

 ence at the expense of the food stored in the seed. The slender 

 vine extends out and around until it comes in contact with 

 some plant part, when it develops the haustoria (or "sinkers" 

 as they sometimes are called) and then the root in the soil 

 dies. 



210. Nutrition of the mistletoe (Phoradendron flavescens). 

 The mistletoe is a well-known plant especially in the southern 



half of the United States, and is often used farther north in 

 Christmas decorations. It is a parasite on a number of trees, 

 especially on red maple and the tupelo, but occurs on the oaks 

 and some other trees. It is a small branched shrub often forming 

 dense tufts on the branches of its host. It is very conspicuous in 

 winter because it holds its leaves while its hosts are bare, and 

 because of its green stems. Having chlorophyll it can manu- 

 facture its own carbohydrates. Its roots penetrate the branches 

 of the trees on which it grows, and it derives its mineral foods 

 and water from its host. 



211. Other parasitic flowering plants are the beech drops 

 (Epiphegus) growing attached to the roots of beech trees, the 

 small mistletoe (Arceuthobium) attached to twigs and branches of 

 the native spruce. The mistletoe of Europe (Viscum album) grows 

 on a great variety of trees, but develops more freely and luxu- 

 riantly on apple trees, the black poplar and certain spruces, trees 

 which have a soft cortex, while it is rarer on the beech, birch, 



