The structure of the needles mesophyll in species of the Pinaceae family with flat leaves

The spatial organization of mesophyll and three-dimensional forms of assimilative cells are considered on the example of 7 species of the Pinaceae family with flattened leaves: Abies cephalonica, A. concolor, A. sibirica, Larix sibirica, Picea omorica, Pseudotsuga menziesii and Tsida canadensis. It was shown that three types of mesophyll cells are distinguished in the flattened needles: palisade, spongy and median. Median cells are appreciable both with well-defined and weak differentiation of assimilative tissue; they can have simple and complex cellular forms.