An arrangement of three Navicula firma mounted in Styrax. Some bubbles/globules in the mountant. Prepared by Watson and Sons Ltd. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo NA 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. 11mm spacer to the camera removed to increase the field of view. Monochrome converted Nikon d850 camera. 56 images stacked in Zerene (Pmax).
Navicula firma Kützing 1844. Published in: Kützing, F.T. (1844). Die Kieselschaligen Bacillarien oder Diatomeen. pp. [i-vii], [1]-152, pls 1-30. Nordhausen: zu finden bei W. Köhne. Page 92, Plate 21, Figure 10. This name is currently regarded as a synonym of Neidium firmum (Kützing) Pfitzer. Source of Synonymy: Pfitzer, E. (1871). Untersuchungen über Bau und Entwicklung der Bacillariaceen (Diatomaceen). In: Botanische Abhandlungen aus dem Gebiet der Morphologie und Physiologie Bd 2. pp. [i]-vi, [1]-189, plus 6 pls. Bonn: bei Adolph Marcus.