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/...
