aka Hairy Ruellia; Ruellia caroliniensis; Acanthaceae (acanthus family)
This plant grows about a foot or two tall, and likes dry soils and a little shade. I’ve yet to find a really good specimen, as they’re all just off narrow part of the trail that sees a lot of foot traffic and, this year, flooding. Not to mention over-enthusiastic trail maintenance personnel, which I’ll rant about tomorrow.
Click on this picture to enlarge, so you can see the lovely details in the petals:
Carolina wild petunia is endangered in New Jersey and extirpated in Pennsylvania.