Louisiana peppergrass (gumbo Z'herbes)

I know very well what wild mustard is, but I'm trying to detect our native Louisiana wild peppergrass. I did searches and turns out that there are at least 7+ DIFFERENT things called peppergrass in deifferent areas. My momma says she hasn't seen any in a long time, but they use to grow wild in the fields (all the chemicals must be wiping them out), but I know for a fact there still around & a guy probably in his 90 stills goes out & finds some sometimes. She said that when you rubbed it, it burned. Anyways, this is an old-time green that use to be used & was often put in Gumbo Z'herbes (gumbo with 7 greens) that was often ate during lent.

I'm looking for some type of positive identification where I can actuaally pick this and not get thoe wrong thing & end up poisoning myself or anything.