cross section: Sambucus stem magnification: 400x

Deep to the periderm is an outer cortex of tightly packed lamellar collenchyma and an inner cortex of open airy parenchyma. Large dark staining tannin ducts are present.

The vascular cylinder consists of a narrow outer ring of primary phloem, a middle ring of vascular cambium and a deeper large ring of primary xylem. Phloem bands of sieve tubes and companion cells are layered and interspaced with parenchyma cells masses and occasional small bundles of sclerenchyma cells. Small masses of calcium oxalate crystals are present. Xylem is separated from the pith by a starch sheath of dark staining parenchyma cells.

The vascular cylinder is divided into narrow columns by radial bands of parenchymatous rays that extend from pith to phloem. Wide phloem rays taper as they dip into the xylem where they merge with the starch sheath. A large parenchymatous pith occupies the center of the stem.