At the left, black, sooty smut infects the fruiting head of a grass so vulnerable to the disease that it's called Smutgrass. It's Sporobolus indicus. The blackness is black spores. Grasses are particularly at risk to smut diseases. Corn (maize), barley, wheat, oats, sugarcane, and forage grasses all suffer smut infections.

Highly edible corn smut; image courtesy of 'Idéalités' and Wikimedia Commons

Probably the most famous smut is shown at the right. The white bags are spore-producing galls of the fungus Ustilago maydis. Immature galls are much prized for their edibility, especially as ingredients in soups and with corn-based dishes such as fillings in tamales or on tacos or quesadillas with melted cheese and topped with salsa, in omelettes, etc.

Among the smuts, when the hyphae parasitizing the host plant are ready to reproduce, the hyphae's cell walls melt, or "gelatinize," and the cells' contents changes into spores. Once the cell walls are completely disintegrated, the spores float away on wind currents. This special kind of spore is called a teliospore and it's may be thought of as a resting stage.

The teliospore may fall onto the ground and perhaps at a much later date, when environmental conditions are good, it germinates to produce a long, tube-like thing, which is the basidium. The basidia -- just as they would on a gill or pore fungus -- then produce basidiospores, and of course new hyphae can germinate from the basidiospores, starting the life cycle over.

In 2021, about 850 species in some 49 genera and 8 families are recognized as belonging to the Smut Fungus order, the Ustilaginales.