I'm not sure the leaves match Nuttallanthus canadensis Dave, they are thinner than those on your plant.
Nuttallanthus texanus is possible, I would say more likely ..
http://www.pbase.com/rodg/imag...
http://wildflowerlense.com/npa...
Is the spur much longer than the calyx? The spurs on yours look quite long, compare them to these photos and the leaves ..
http://www.missouriplants.com/...
http://luirig.altervista.org/f...
