fungus /fun′gəs/ pl. fungi [L, fungus, mushroom] , a eukaryotic, thallus-forming organism that feeds by absorbing organic molecules from its surroundings. Fungi lack chlorophyll and therefore are not capable of photosynthesis. They may be saprophytes or parasites. Unicellular fungi (yeasts) reproduce by budding; multicellular fungi, such as molds, reproduce by spore formation. Fungi may invade living organisms, including humans, as well as nonliving organic substances. Of the 100,000 identified species of fungi, 100 are common in humans and 10 are pathogenic. See also fungal infection. −fungal, fungous, adj.
