Cross-section of a typical monocot root shows following structures. Which of the following layers are formed by single layer of compactly arranged, barrel-shaped parenchymatous cells?

Epiblema is the outermost covering of the root formed by single layer of compactly arranged, barrel-shaped parenchyma cells. The cells are characteristically thin-walled, since they are involved in absorption of water. A cuticle and stomata are absent. Some of the epiblema cells are produced into long unicellular projections called root hairs. Hence, the epiblema is also known as piliferous layer.