Club-shaped in valve view, with swellings at both the narrow and wide ends, wedge shaped in girdle view; large; one or more (commonly 3) ...
Club-shaped in valve view, never with swelling at wide end, wedge shaped in girdle view; central area commonly offset from widest part of...
Club or violin-shaped in valve view, wedge shaped in girdle view, much smaller than [Didymosphenia]; may be single stigmata at the edge o...