Many different types of stems exist in a variety of sizes and shapes, adapted for a variety of functions. The stem in the image above is one with thorns. Thorns are sharp and pointed, and they protrude from plant stems. Made of vascular tissue, these structures supply more benefits than meets the eye. In addition to providing a defense mechanism for the plant and its crucial organs (the flowers), thorns have been shown to shade or insulate the plant, which is advantageous to an immobile organism in a harsh environment.