The cell size in the primary cortex is larger than that of the secondary cortex. There is primary xylem tissue in the pith. Secondary xylem rays are usually 1-3 layered though sometimes as much as 8 and are heterogenous. Primary xylem rays are 1-2 layered. The stem has a single layered epidermis.
Epidermal cells are either hexagonal or ovoidal.
There are both glandular and eglandular hairs with glandular being predominate. They are both unicellular and multicellular. Collenchyma are present particularly at the angle of the stem. The cortex is 5 layered and parenchymatic. There is a sclerenchymatic sheath on the phloem part and the cambium is not distinguishable.