Morphological Variability of Navicula radiosa KÜTZ. f. nipponica SKV, and var. tenella (BRÉB. ) GRUN. (Navicula cryptotenella LANGE-BERTALOT)

Abstract

The investigation was carried out on attached algae collected from the River Takiya in Fukushima prefecture. This sample contained a mixed population belonging to Navicula radiosa. We can identify two taxa, N. radiosa f. nipponica and N. radiosa var. tenella, judging from their morphological differences. The differences are recognized in the length and the breadth of the valve, striae in 10μm and their appearance including puncta, and margin of the valve especially in their degree of obliquity.