American Lady

Vanessa virginiensis is most easily distinguishable by its two large eyespots on the ventral side, whereas V. cardui has four small eyespots and V. annabella has none. V. virginiensis also uniquely features a white dot within the forewing subapical field, set in pink on the underside and usually also in the dorsal side's orange field.
The largest spot in the black forewing tips is white in V. cardui, pale orange in this species, and orange in the West Coast species. The latter also has a purer orange background color of the dorsal side, as opposed to the darker and (especially in V. virginiensis) redder hue of the other two.