A stamen is the part of a flower that makes pollen. They are usually in the center of the flower, and have stalks called filaments with the pollen produced on anthers at the top of the stalks.
A stem is the part of the plant that holds up the leaves and flowers. Stems on some kinds of plant continue to get bigger and bigger, and eventually turn into branches.
Another word for stem is stalk.
A tendril is a part of a plant that has no leaves. Tendrils grow at the tip of the new growth on a plant, in a spiral shape. Tendrils wrap around anything they encounter, and become supports for the growing plant.
Thorns grow on many plants to protect them from animals that want to eat them. Thorns are very sharp and are often hooked so they catch onto your skin and clothes. The thorns in the picture are on a rose bush. Thorny plants are often referred to as briar or brambles.
A tree's trunk is the main supporting structure of the tree. Tree trunks are covered with bark and branches grow out from the sides of the tree's trunk.
As the tree gets older its trunk gets thicker. Wood for making furniture or houses out of is cut from the trunk of a tree.
