The fungi (singular, fungus) once were considered to be plants because they grow out of the soil and have rigid cell walls. Now they are placed independently in their own kingdom of equal rank with the animals and plants and, in fact, are more closely related to animals than to plants. read more
Because under the microscope, their cells look much closer to animal tissue. Their metabolic trends don’t really sit to well within the plant or animal kingdom. read more
Almost all plant species are photosynthetic. no fungi are photosynthetic. - Plants have cellulose in their cell walls. many fungi have chitin in their cell walls. - the majority of plant species reproduce via seeds. fungi reproduce via spores. - fungi digest food outside their bodies, unlike most animals which ingest food and digest it inside their bodies. read more
Now, fungi are known to actually more closely related to animals than to plants and are now classified in their own kingdom. Fungi are not plants. The part of the fungus that we see is only the "fruit" of the organism. read more