It's not impossible that it was planted but it's a strange place to do that. It has a lot in common (the pronounced teeth along the spine and edges of the leaves) and the multiple stems with other sightings on the PNR (not all logged to NatureMapr) that remain a bit of a mystery. On the other hand, another sighting that I initially put in this uncertain category because of it's toothiness (4486591) and you identified as D. revoluta did indeed turn out to be D. revoluta when it flowered. One of the other quirky things about the current sighting is that all the flower stalks stay below the tops of the leaves (although this could just have been water stress, given its location, at time of stalking).