Scanning electron micrographs of Gastromyxum rafii n. sp. and Gastromyxum bulani n. sp. Gastromyxum rafii spores have rounded ends (a) and are rhomboid in the sutural view (b). Gastromyxum bulani spores are lightly fusiform in the valvular view (c), sigmoid in the sutural view (d) and have more pointed ends with an apical opening for the polar filament to be released through (inset d). Both species have smooth valves and non-prominent sutural lines. Each valve has one rounded/pointed end which forms a nipple-like structure at its apex, with the other end concealed beneath the apex of the opposing valve. Scale bars 3 μm (inset 1 μm).