Aspect of a vascular bundle observed with the objective of 40x. Going from outside (inferior part of the image) inwards (superior part of the image) the stem are visible the following structures: cortical parenchyma, support tissue formed by collenchyma, showing blue-stained thick cellulose cell walls, vascular elements of phloem, vascular cambium (meristem), xylem, and medullar parenchyma. In the xylem, we can observe the vascular elements and the xylematic radial parenchyma. The cambium is formed by the fascicular part (yellow) (integrated in the vascular bundle) and the interfascicular part (located between consecutive vascular bundles)