pith hair
1.We have observed the following characteristics of anatomical structure and development: (1) The primary roots belong to archetype and the lateral roots occur in the position toward the xylem of the vascular cylinder; (2) The root endodermis consists of thicken casparian strips, and there are from two lo four layers parenchyma cells near the pericycle; (3) the pith and resins canals are absent in the toots; (4) Secondary structure occurs in the root hair zone, and vascular cambium is formed from the parenchyma cells between the primary xylem and primary phloem; (5) Tanning materials are abundant in pericycle cells and phelloderm cells; (6) Sclereids are found in secondary phloem, and rays are rather rich in secondary xylem.
