Thus far we have spoken of plants that have roots and foliage and that depend on themselves. They collect the raw materials and make them over into assimilable food. They are =independent=. Plants without green foliage cannot make food; they must have it made for them or they die. They are =dependent=. A sprout from a potato tuber in a dark cellar cannot collect and elaborate carbon dioxide. It lives on the food stored in the tuber. [Illustration: FIG. 131.—A MUSHROOM, example of a saprophytic plant. This is the edible cultivated mushroom.] _All plants with naturally white or blanched parts are dependent._ Their leaves do not develop. They live on organic matter—that which has been made by a plant or elaborated by an animal. The dodder, Indian pipe, beech drop, coral root among flower-bearing plants, also mushrooms and other fungi (Figs. 131, 132) are examples. The dodder is common in swales, being conspicuous late in the season from its thread-like yellow or orange stems spreading over the herbage of other plants. One kind attacks alfalfa and is a bad pest. The seeds germinate in the spring, but as soon as the twining stem attaches itself to another plant, the dodder dies away at the base and becomes wholly dependent. It produces flowers in clusters and seeds itself freely (Fig. 133). [Illustration: FIG. 132.—A PARASITIC FUNGUS, magnified. The mycelium, or vegetative part, is shown by the dotted-shaded parts ramifying in the leaf tissue. The rounded haustoria projecting into the cells are also shown. The long fruiting parts of the fungus hang from the under surface of the leaf.] =Parasites and Saprophytes.=—A plant that is dependent on a living plant or animal is a =parasite=, and the plant or animal on which it lives is the =host=. The dodder is a true parasite; so are the rusts, mildews, and other fungi that attack leaves and shoots and injure them. [Illustration: FIG. 133.—DODDER IN FRUIT.] The threads of a parasitic fungus usually creep through the intercellular spaces in the leaf or the stem and send suckers (or haustoria) into the cells (Fig. 132). The threads (or the hyphæ) clog the air-spaces of the leaf and often plug the stomates, and they also appropriate and disorganize the cell fluids; _thus they injure or kill their host_. The mass of hyphæ of a fungus is called =mycelium=. Some of the hyphæ finally grow out of the leaf and produce spores or reproductive cells that answer the purpose of seeds in distributing the plant (_b_, Fig. 132).