Interesting slide this. Licmophora flabellata (written as flabellatum on the slide) on algea. Prepared by Edmund Wheeler. Olympus BHB microscope using 450nm LED light. As well as the wider field of view, I imaged part of it using the 20x Nikon Plan Apo NA 0.65 objective. Olympus Aplanat Achromat condenser, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 15 images stacked in Zerene (Pmax).
Licmophora flabellata (Greville) C.Agardh, 1831. Published in: Agardh, C.A. (1831). Conspectus criticus diatomacearum. Part 3. pp. 33-48. Lundae [Lund]: Literis Berlingianus. Page 42.