Corms are short, vertical, swollen underground plant stems that serve as a storage organ that some plants use to survive winter or other adverse conditions such as summer drought and heat. They consist of one or more internodes with at least one growing point, generally with protective leaves modified into skins or tunics. The tunic of a corm forms from dead petiole sheaths—remnants of leaves produced in previous years. They act as a covering, protecting the corm from insects, digging animals, flooding, and water loss. Corms are structurally plant stems, with nodes and internodes with buds and produce adventitious roots. On the top of the corm, one or a few buds grow into shoots that produce normal leaves and flowers. Corms can form many small cormlets called cormels, from the basal areas of the new growing corms, especially when the main growing point is damaged. These propagate corm-forming plants. Corms are sometimes confused with true bulbs; they are often similar in appearance to bulbs externally, and thus erroneously called bulbs. However, corms are stems that are internally structured with solid tissues, which distinguishes them from bulbs, which are mostly made up of layered fleshy scales that are modified leaves. As a result, a corm cut in half appears solid inside, but a true bulb cut in half reveals that it is made up of layers. Examples of plants that grow from corms include crocus, gladiolus, and taro.