A strew slide from Llyn Crafnant, Snowdonia, North Wales. Per H.G.Gleave. Mounted in Aroclor and dated February 1975. Good range of species present. No makers name but this is by Bernard Hartley. Olympus BHB microscope using 450nm LED light. I chose a couple of diatoms for high magnification imaging. 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. Image stacks prepared in Zerene (Pmax).
Pinnularia sp. (maybe Pinnularia divergens, but that is very tentative). 29 images stacked. Pinnularia divergens 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 57, Plate XVIII(18), Figure 177. Used to be known as Navicula divergens (Schmidt’s Atlas, Plate 44, Figure 6).
Epithemia sp. (I think this could be E. gibba). 16 images stacked. Epithemia gibba (Ehrenberg) 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 35, Plate 4, Figure 22. This name is currently regarded as a synonym of Rhopalodia gibba (Ehrenberg) O.Müller.
There is an entry from Bernard Hartley’s Sample and Strew Slide Collection PDF for this slide – slide 632 – accessed from here.