Parasite

a plant or animal that lives at the expense of another. Parasitic animals may live on the outside, as lice and ticks; or they may reside in the interior, as the tapeworm of man and beast. Parasitic plants are to be distinguished from air plants that fasten themselves to the bark of a tree and live mainly on the air or, at most, on rotten bark and plants, and from plants that feed on dead and decaying matter, but the one shades off into the other so that it is difficult to draw a fast line. A parasitic plant sends roots or absorbing branches into the sap wood of its host and feeds on the sap found there. Quite a number of flowering plants are parasites. Some are green, as mistletoe and bastard toad flax; others are waxy, as dodder and Indian pipe. Rusts, smuts, and mildews which attack crops are parasitic fungi. Originally, a parasite was a person, one who sat beside another, a hanger-on at the table of some rich patron, with the probability of winning a welcome by flattery and sycophancy. See Tapeworm; Mistletoe; Dodder