Smut fungi

Smut fungi are plant pathogens in the Basidiomycota in the subphylum Ustilaginomycotina. About 1700 species of smut fungi affect > 4,000 spp. of angiosperms. They have a less complex life cycle than rust fungi, with only one host and usually only two spore stages; teliospores and basidiospores. The fungus grows within the plant forming loose masses of dark-colored spores (teliospores) in infected plant tissues or in tumor-like galls filled with teliospores. The name "smut fungi" refers to the black dusty masses of teliospores that resemble soot (smut in old literature). 

Teliospores are the main dispersal stage of smut fungi. When the teliospores germinate they produce yeast-like basidiospores, which can go on to form the next stage resulting in the infection of additional host plants.  Many smut species overwinter as teliospores, while others overwinter as mycelium in infected grain. The image below shows corn smut galls, which replaced normal corn kernals.