Grows with Yellow star-tulip (Calochortus monophyllus) and White Globe Lily (Calochortus albus) on the western slopes of Nevada County, CA near Nevada City at 2500'. This is the only photo I have. There are only a few of these each year (4).

Needless to say, I don't get to see a lot of (any, that is) Calochortus, but here's the list of Calochortus for Nevada county:
http://www.calflora.org/cgi-bi...

I haven't tried to key it out or anything but here are what appear to be the only possibilities...
Calochortus monophyllus, though it would be a pale-flowered one:
http://www.google.ca/search?q=...

Or Calochortus alba:
http://www.google.ca/search?q=...

And apparently, they hybridize (not to say that's it but just a possibility):
http://calphotos.berkeley.edu/...

Thanks a hybrid would make a lot of sense. Ill try to get more shots and measurements.