The stems inside area, under the sapwood, contains xylem, phloem, cambium, sapwood, heartwood and pith. Next comes the xylem and the cambium, then phloem, sapwood, heartwood and in the center of a tree is the pith. Herbacious plants have a different structure consisting of epidermis, cortex, pith and a series of vascular bundles. The fruit of a plant is actually a ripened ovule. Fruits are usually classified by their structure and number of ovules.
Simple fruits can be fleshy or dry.
They develop from a simple ovary. An example is a berry which is a simple fruit that has a fleshy tissue. Other examples include tomatos and cranberries. A drupe has a stone in the center of the fruit which is its seed. Examples of drupes are olives and peaches.