Stem, part of a plant from which the leaves and flowers sprout. Formed by the growing tip as it emerges from the seed after germination, it may divide repeatedly to produce branches and twigs. A stem may be very short, as in low-growing plants in which the leaves appear to sprout directly from the roots. In trees the stem is represented by the trunk, which may be over 100 ft (30 m) high. Stems are responsible for support and contain strengthening tissues, such as wood. They also carry food and water between the leaves and roots. Green stems carry out photosynthesis; modified stems, such as the tuber, act as food stores.