FIGURES 19–24 in Pinnularia sikkimensis sp. nov. (Bacillariophyceae), from Eastern Himalayas and its distribution in Southeast Asia

FIGURES 19–24. Pinnularia sikkimensis sp. nov. SEM. 19. External view of the whole valve. 20. Girdle view of the whole valve. 21, 22. External view of poles showing the distal raphe endings. 23. External view of valve centre, showing the proximal raphe endings. 24. Magnified view of striae patterns showing small areolae and covered by silicified hymens. Scale bars: Figs 19, 20: 2 µm; Figs 21–24 = 1 µm.