The primary cambium is found in the stem and root between the phloem and xylem cells, and by division gives rise to the secondary phloem and xylem in woody dicotyledonous plants.

• 它纵贯于根，茎等器官的木质部和韧皮部之间，是具有分生能力的组织。通过形成层的分裂可以在木本的双子叶植物中形成次生木质部和次生韧皮部。