<P> The shape of parenchyma cells varies with their function . In the spongy mesophyll of a leaf, parenchyma cells range from near - spherical and loosely arranged with large intercellular spaces, to branched or stellate, mutually interconnected with their neighbours at the ends of their arms to form a three - dimensional network, like in the red kidney bean Phaseolus vulgaris and other mesophytes . These cells, along with the epidermal guard cells of the stoma, form a system of air spaces and chambers that regulate the exchange of gases . In some works the cells of the leaf epidermis are regarded as specialised parenchymal cells, but the modern preference has long been to classify the epidermis as plant dermal tissue, and parenchyma as ground tissue . </P> <P> Shapes of parenchyma: </P> <Ul> <Li> Polyhedral </Li> <Li> Stellate (found in stem of plants and have well developed air spaces between them) </Li> <Li> Elongated (found in pallisade tissue of leaf) </Li> <Li> Lobed (found in spongy and pallisade mesophyyll tissue of some plants) </Li> </Ul> <Li> Stellate (found in stem of plants and have well developed air spaces between them) </Li>

The structure and function of parenchyma collenchyma and sclerenchyma