An arrangement of three Pleurosigma angulatum. Mounted in Styrax. Some issues with the mountant (crystallization?), and the slide was very low contrast. Prepared by Watson and Sons Ltd. Olympus BHB microscope using 450nm LED light. Single one imaged using a 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. 11mm spacer to the camera removed to increase the field of view. Monochrome converted Nikon d850 camera. 32 images stacked in Zerene (Pmax).
Pleurosigma angulatum (J.T.Quekett) W.Smith 1852. Published in: Smith, W. (1852). Notes on the Diatomaceae with descriptions of British species included in the genus Pleurosigma. Annals and Magazine of Natural History, Series 2 9: 1-12, 2 pls. Page 7, Plate 1, Figures 7, 8 [as var. beta], 9 [as var. gamma].