Cosmioneis hawai’iensis is more broadly rounded and more strongly capitate than C. lundstroemii. Cosmioneis hawai’iensis should also be Cosmioneis capitata which is strongly capitate but narrower and less rounded than C. hawai’iensis. In addition, C. capitata is 11 μm in width, while C. hawai’iensis is 12-15 μm in width.