The magnification series (Figs. 4–6) impressively shows the network of cellulose microfibrils in the primary wall. The protuberances marked with arrows are examples of cellular structures originating from the pore apparatuses in the underlying secondary wall. In the last image, the diameters of the microfibrils become measurable at the highest magnification. Within the limits of measurement accuracy, the finest visible strands have diameters of approximately 10 nm. The order of magnitude of these measurements corresponds well with the findings of Giddings et al. (1980). They had determined that during the formation of the primary wall, individual production apparatuses of cellulose microfibrils (the so-called rosettes) produce microfibrils with a diameter of 5 nm. They were further able to show that during the formation of the secondary wall, hexagonally arranged arrays of rosettes produce complex fibrils with a diameter of 28 nm, which form the basis of the secondary wall.

Such instructive depictions of the primary cell wall in desmids are rare even in the life sciences literature. This is likely due to the fact that the ultrastructural details of the cellulose walls, as well as the processes involved in their formation, were investigated using transmission electron microscopes in the 1980s and 1990s. SEMs of the quality required to capture images like the one shown above were simply not available at that time.