Cuphea llavea 'Vienco Lavender', I believe.

You never provided a location. Also curious how you placed your plant in the Scorzonera genus. If that part is accurate, there are only two Scorzonera species in the US. The first is S. hispanica, which is only found in northern California. The second is S. lacinata. That one does look something like your plant, and is found along a line from northwest Montana to the panhandle of Texas. It was also recently found in southern Oklahoma. Here is a link that might be useful: False Salsify

It looks like St. John's-wort aka Hypericum perforatum L. Here is a link that might be useful: http://search.aol.com/aol/imageDetails?s_it=imageDetails&q=yellow+mentzelia+oklahoma&img=http%3A%2F%2Fbotany.csdl.tamu.edu%2FFLORA%2Fdcs420%2Ffa02%2Ffa02084.jpg&v_t=nscpsearch&host=http%3A%2F%2Fbotany.csdl.tamu.edu%2FFLORA%2Fimaxxloa.htm&width=124&height=157&thumbUrl=http%3A%2F%2Ft0.gstatic.com%2Fimages%3Fq%3Dtbn%3AANd9GcRGUoAU-6AGhBIXXNptF1cuouBCSyRcthJhyFDyHDHpJmcsrGVbnsbiFADb%3Abotany.csdl.tamu.edu%2FFLORA%2Fdcs420%2Ffa02%2Ffa02084.jpg&b=image%3Fv_t%3Dnscpsearch%26page%3D3%26q%3Dyellow%2Bmentzelia%2Boklahoma%26s_it%3DimageResultsBack%26oreq%3Daf9f5dfb54294b7fa45b7ee13e7a846d%26oreq%3D51cd9061c3384ee8bf7e0694f39d25cd&imgHeight=403&imgWidth=319&imgTitle=Mentzelia+oligosperma+-+Native&imgSize=63170&hostName=botany.csdl.tamu.edu

They look more like Cyclamen than any native I know. Any chance you took any pictures from less than 6 ft away?