A new morphotype of chrysophycean stomatocyst from the pond of Peter the Great Botanical Garden (Saint Petersburg)
The paper deals with the problem of identifying chrysophycean stomatocysts. An historical essay of classification schemes for chrysophycean stomatocysts is presented. It is noted that the stomatocysts are widely used in palaeolimnological studies. A new 395/13 morphotype of a chrysophycean stomatocyst from the pond of Peter the Great Botanical Garden is described on the basis of plankton samples. The stomatocyst is spherical (5.3 μm diam.) and has a short cylindrical collar (1.8 μm diam., 0.2 μm high), with a conical pore (0.3 μm diam.). The entire stomatocyst surface is covered with rounded scabrae 0.1–0.2 μm in diameter. Morphology of the new stomatocyst morphotype was studied and its original micrograph was made with a scanning electron microscope.