Fungi differ from plants in several ways.

Fungi have no roots, stems or leaves. Instead, fungi are solely comprised of mycelia. These mycelia are networks of fungal cells.

Fungal cells do not contain photosynthetic chloroplasts. This means that fungi cannot produce their own energy in photosynthesis, like plants do. Instead, fungi gain their energy from plants. This means that they are heterotrophic organisms.

Some fungi live in symbiosis with trees and plants, whereas others act as decomposers. 

The visible part of a fungi is called the fruit body. It is a reproductive structure that releases spores. Only some species of fungi produce them.