Which of the following is NOT a tissue found in the stem?

In the context of plant anatomy, the stem is composed of several key types of tissues that play vital roles in support, transport, and growth. Xylem is responsible for water and mineral transport from roots to leaves, while phloem transports organic nutrients, particularly sugars produced through photosynthesis. Cambium is a type of meristematic tissue that is responsible for the secondary growth of stems and roots, allowing plants to increase in diameter by producing new layers of xylem and phloem.

While "stele" refers to the central part of a stem that contains the vascular tissues (xylem and phloem) as well as surrounding supportive tissues, it is a broader term that describes the arrangement of vascular tissues within the stem rather than a specific tissue type itself. Therefore, when asked to identify which option is not a tissue found in the stem, "stele" correctly stands out as it encapsulates the vascular structure rather than being a defined tissue like xylem, phloem, or cambium.