The highbush blueberry has two major types of roots: (1) pencilthick storage and anchor roots and (2) fine, thread-like roots, often only 50 pm in diameter (Figure 3-1). The latter are the feeder roots responsible for nutrient absorption. The roots are composed of a thin root cap covering the apical meristem. The cap is somewhat muci­ laginous and aids the root’s penetration of the soil while protecting the meristematic tissue. The meristem tissue undergoes rapid cell division and is responsible in part for adding new cells to the root. The root structure 12-25 mm behind the apex shows a homogenous cortical region of 3-4 cell layers about 40 pm thick. The cells are simple parenchyma and alternate with one another in successive concentric layers. The cortex is surrounded by a poorly developed epidermal layer of symmetrical cells, the outer surfaces of which are convex. The cortex itself surrounds a single layer of cells called the endodermis, beneath which lies the vascular cylinder, composed of the vascular system and associated parenchyma. This inner cylinder, also called the stele, is about 30 pm in diameter. The blueberry root has no root hairs. The anatomy of older roots is similar to that of the stem.