Guard cells are specialized cells that regulate the opening and closing of stomata, whereas lower epidermis is the outermost layer of cells on the lower surface of leaves. One visible difference between lower epidermis and guard cells is that guard cells are more prominent and have a distinct shape compared to the flattened and irregularly shaped cells of the lower epidermis. Additionally, guard cells have openings between them, which form stomata, whereas the cells of the lower epidermis do not.
