The most common plant part to sprout offspring is the stem. There are buds on the stem which help the plant to breed.

In some plants a bud low down on the stem will sprout a shoot which grows horizontally along the ground. This side shoot is called a runner. It grows buds too and when a bud touches the ground it sprouts roots and leaves and becomes a small copy of the parent plant. The runner may send food from the parent plant to help it in grow but in time the runner will whither and the two plants will live separate lives.

The potato plant sends out runners which grow underground. Part of each runner swells with food and becomes a tuber which we call the potato. If the potato plant is left in the ground at the end of the growing season it rots and each potato becomes separated from all the others. In the following year each potato can grow into a new plant. The iris grows a thicker underground stem which can be broken up and each part can form a separate plant.

The bulb has a short stem. Look at the bottom of an onion and find a ring of fibrous roots. They mark the position of the stem. When you cut open the onion you will find that the stem is only a flat disc at the base of the bulb. Most of the bulb is made from the bases of leaves swollen with food that are growing out of the stem. There are buds between the leaf bases in a bulb. These can take in food made from the leaves and swell up to form side bulbs as seen in the daffodil. In time these can separate from the parent bulb and form plants on their own.

The crocus grows from an underground stem called a corm. This stem is different from other stem because it is short and fat. The flower and leaves of the crocus grow from a bud at the top of the stem but side buds on the stem may also swell up and make corms too.

When a plant reproduces by growing offspring on its stem it reduces the risk of failure. The parent plant is already growing in ground which is suitable for its offspring so when they start to grow they have a chance to succeed. The parent can also supply a large amount of food to help its offspring grow. Plants which are grown from stems are different to plants which are produced by seeds. Plants from seeds are different from their parents because they contain material from two plants. Plants from stems are exact copies of the parent. The word use to describe a plant or animal that is an exact copy of its parent is clone.