An arrangement of two Frustulia rhomboides from Cherryfield, Maine. Mounted in Styrax and dated October 1969. Prepared by RI Firth. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 25 images stacked in Zerene (Pmax). The mountant was actually really nice and clear, but I did replace the background as I often do with my images. Funnily enough just to the side of the diatoms was what I think is a single pollen grain.
Frustulia rhomboides (Ehrenberg) De Toni 1891. Published in: De Toni, G.B. (1891). Sylloge algarum omnium hucusque cognitarum. Vol. II. Sylloge Bacillariearum. Sectio I. Rhaphideae. pp. [i-iii]. [i]-cxxxii, 1-490. Patavii [Padua]: Sumptibus auctoris.Page 277. Basionym: Navicula rhomboides Ehrenberg.