FIG. 8. — A, B in The culture collection of cyanobacteria and microalgae at the French National Museum of Natural History: a century old but still alive and kicking! Including in memoriam: Professor Alain Couté

FIG. 8. — A, B, Staurastrum polytrichum (MNHN-ALCP-2019-823.2), solitary cells with very deep median constriction (isthmus) dividing the cell into two semicells or hemisomates. SEM images show triangular semicells in apical view with straight sides, broadly rounded angles and many inframarginal spines (sp). Cell surface ornemented with pores. C, D, Cosmarium connatum (MNHN-ALCP-2019-832.1), solitary cells, lateral view with a barely marked isthmus (i) and smooth cell wall with pores. E, F, Synura petersenii (MNHN-ALCP-2019-877.3), colony and scales morphology. SEM images show rows of silica scales around individual cells. Scales with well-developed thorns (t). Ribs (r) running from the thorn to the scale perimeter up to the outer rim. G, H, Micrasterias furcata (MNHN- ALCP-2019-821.5), solitary cells, deeply constricted and dorsiventrally compressed. Semicells dissected into a polar lobe (p) divided into the second order. Lateral lobes (l) themselves divides into second and third order (or many times) ending with two simple spines (s). A, C, E, G: light microscopy; B, D, F, H: SEM micrographs. Scale bars: A, C, E, G, 20 µm; B, D, F, H, 10 µm.