For further discussion amd diagrams, it is recommended that the student refers to a introductory botony or biology text, which can be found in most libraries. A true root's origin is from the seedling . Adventitious roots originate from the stem . A herbaceous stem is typically soft, succulent and green. A woody stem is produced only in second and subsequent years of certain plants, usually trees, shrubs and some vines.
Many dicots produce wood.
A few monocots, like palm trees, bamboo and the hala tree, produce a woody-type growth differing structurally from dicot wood. Both are outer coverings on stems. The epidermis is a single layer found on herbaceous stems. Bark is a multi-layered woody covering on woody stems. The cambium a. is found directly under the epidermis or bark b. is composed of a single row of cells which divide and produce all new cells, increasing the thickness of the stem.