tissue composed of more or less elongate cells arranged in radial columns. Palisade mesophyll occurs with *spongy mesophyll
as a ground tissue in the leaves of many mesophytes. Here the palisade mesophyll is usually on the adaxial (upper) side of the leaf, whereas in many xerophytes it forms the bulk of the mesophyll and is present on both sides of the leaf. When the stem has taken over much or all of the photosynthetic work of the plant, the cortex may consist largely of palisade parenchyma.