An electron microscopic study of tubules in the nuclei of Selaginella leaf cells.

In the light microscope the nuclei of the leaf cells of Selaginella martensii show ring-shaped inclusions. These rings are Feulgen positive and most probably contain DNA. An electron microscopic examination of these ring-shaped inclusions shows that they are composed of closely packed tubular elements which have a constant diameter and unknown length. These bundles are often surrounded by a number of larger tubular elements which may be built up of tubular subunits.