Citrus, is a genus of plants belonging to the Rutaceae family yielding pulpy fruits. The cross section shown on this page belongs to Georges Roux collection. The petiole is cylindrical with vascular bundles on a single ring. Secondary xylem (X2; dotted red lines) is well developped.  Primary xylem (white arrow) is found toward the center of the petiol that is occupied by parenchyma (par; medular parenchyma). Secretory cavities (sc) are observed in the cortical parenchyma at periphery of the petiole.