Czarn. and Blinn 1979
Gomphonema carolinense is larger, heteropolar and more clavate-elliptic. The Gomphonema parvulum-complex has narrower valves with more clavate-elliptic forms (e.g. G. parvulum var. lagenula Frenguelli) and parallel to only slightly radiate striae.
Hagelst.
Kütz.