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EXAMINING WOODY STEMS Let's look very carefully at this willow (or horse chestnut) stem. It is like wood, because it's part of a tree. It's not at all the same as a flower stem. There are roots at the bottom (base) of the stem, just like plants have, and the woody stems almost always grow upward. Plants grow toward light. Most trees are outside, and the sun is their light. Trees grow toward the sun, and spread their arms (limbs) as though to welcome the sunlight. Do you see the little swollen places on the stem? They are called "nodes," and they are the places where leaves will grow. On trees that blossom, the nodes are the places where flowers will bloom, and then leaves will come out from the nodes also. On trees that bear fruit, like peach trees, the fruit will grow where the flowers are. Nodes have a lot of jobs to do! In the fall, when the leaves drop off, there will be little marks on the stems where the leaves were. Those marks are called "leaf scars." Above each leaf (if it is on the stem) or leaf scar (if the leaf has fallen), there is another tiny swollen place. That is called a "lateral bud." The buds have tiny "scales," which are like lids, and they remain there after the leaves are gone. The bud scales show us where new growth began on the stems. There is another bud on the very end of the stem. It is called the "terminal bud" (the word "terminal" means "end"). The spaces between the nodes, where there aren't going to be leaves, are called "internodes," and they are not all the same. Part of what makes plants interesting is that their leaves and flowers (and fruits) are uneven. On the internodes of some stems, like birch, horse chestnut, and cherry, you can see pores along the internodes. These pores are called "lenticels" (pronounced "len-ti-cells"). The lenticels help the tree to take in water and air. If you put the base of a willow stem into some potting soil and keep it watered, it will grow roots and the nodes will develop leaves. Then, stems will grow out from where the leaves were, and you'll have another willow tree! Make a list of all the parts of the stem, and then look at other kinds of stems to see if they have the same parts. Some kinds of plants have different looking parts, but they do the same things. The nodes on a mint stem, for example, are fat places that go all the way around the stem--they aren't swollen only on one side of the stem. Several leaves, going in all directions, will grow out from the nodes of a mint stem. Mint stems are interesting for another reason: they are sort of square. Isn't that a surprise?  Any problems with this page? Send URL to
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