👉 A pteroid is a type of plant organ that is composed primarily of xylem and phloem. It is an endosperm, which is the part of a plant that stores water and nutrients for its roots and leaves. Pteroids can be found in a variety of plants, including grasses, trees, and shrubs. Pteroids are also known as sponges or xylem organs. They are specialized structures that allow plants to store water and nutrients within