The function of the root cap is to cover and protect the cells at the end of the root of a plant. It also assists in growth, as it secretes a lubricant that enables better movement through the soil. The lubricant secreted is a glycoprotein mucilage.
Almost all plants contain root caps. Root caps consists of masses of parenchymal cells. A root cap may be referred to as a calyptra. Statocytes in this tissue assist the plant in gravity perception as it is growing. There are some aquatic and parasitic plants that do not contain root caps. Instead, they have sac-like structures that are known as root pockets.