Ammannia coccinea- Scarlet Toothcup
This plant has an interesting history in NJ. It was first recorded in NJ in Camden County in 1866-1870 at a ballast dump. It was then not seen until July 30th 2012 by Mary and Charles Leck in Mercer County. The third sighting was by me in Burlington County on 09.14.15. The plant is native, but not considered native to NJ. So maybe birds are spreading it from wetlands as they migrate. I guess no one can say for sure, but it's certainly interesting.