An arrangement of three Nitzschia scalaris. No makers name, but prepared by Laurence Hardman. Olympus BHB microscope using 450nm LED light. As well as the wider field of view, I imaged part of one using the 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 45 images stacked in Zerene (Pmax). Striae spacing approximately 948nm. Puncta spacing varies much more, one pair (middle to middle) measured at 474nm, another even just about resolving at 341nm middle to middle. Distances measured in ImageJ.
Nitzschia scalaris (Ehrenberg) W.Smith 1853. Published in: Smith, W. (1853). A synopsis of the British Diatomaceae; with remarks on their structure, function and distribution; and instructions for collecting and preserving specimens. The plates by Tuffen West. In two volumes. Vol. I. pp. [i]-xxxiii, 1-89, pls I-XXXI. London: John van Voorst, Paternoster Row. Page 39, Plate XIV [14], Figure 115. This name is currently regarded as a synonym of Tryblionella scalaris (Ehrenberg) Siver & P.B.Hamilton 2005. Published in: Siver, P. & Hamilton, P.B. (2005). Observation on new and rare species of freshwater diatoms from Cape Cod, Massachussets, USA. Canadian Journal of Botany 83: 362-378. Page 374.