What appearance do galls caused by corn smut have?

Galls caused by corn smut, a fungal disease also known as Ustilago maydis, typically exhibit a swelling appearance on the affected plant tissues. This swelling occurs as the fungus grows and expands within the host cells, leading to abnormal growths that can change the shape and structure of the plant tissues. These galls are often described as swollen or enlarged areas that can appear on various parts of the corn plant, including ears, stalks, and leaves. The galls can be grayish-white to black in color once mature, especially when they are filled with spores. This distinctive appearance is a hallmark of corn smut infection, differentiating it from other types of plant diseases and damage.