An arrangement of two Neidium tumescens from Cherryfield, Maine. Fossil freshwater material. Mounted in Styrax and dated December 1968. Very nice and clear mountant. Prepared by RI Firth. 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. Monochrome converted Nikon d850 camera. 49 images stacked in Zerene (Pmax). Couldn’t get close enough to use the 63x Leitz Pl Apo objective.
Neidium tumescens (Grunow) Cleve 1894. Published in: Cleve, P.T. (1894). Synopsis of the naviculoid diatoms. Part I. Kongliga Svenska Vetenskapsakademiens Handlingar Series 4 26(2): 1-194, 5 pls. Page 70. Basionym: Navicula tumescens var. Grunow 1877. Published in: Schmidt, A.[W.F.] (1877). Atlas der Diatomaceen-kunde Series II: Heft 13. pp. pls 49-52. Aschersleben: Verlag von Ernst Schlegel. Plate 49, Figure 10 (as ‘Navicula (firma var.) tumescens‘).