On the Morphological Variability of the Diatom Karayevia Suchlandtii (Bacillariophyta)

This scanning electron microscopy study investigates morphological features of the frustule of the diatom algae Karayevia suchlandtii. The study is based on material collected from the Svir River tributaries (Lake Ladoga basin): Ivina, Yanega, Uslanka,Vazhinka, Oyat, Pasha. Quantitative (the valve length and width, the number of striae in 10 µm) and qualitative (the valve shape and the shape of axial areas, the stiae arrangement) characteristics are analyzed. In the surveyed populations of K. suchlandtii, the minimum values of the valve size are smaller than those given in the original description and the literary, that makes it possible to extend the diagnosis of the species.