Nard,
A quick check turned this up on the old board:

“PS I've just been rummaging among some old anthologies and I've also found ‘Lorelei of the Red Mist’ in an old Asimov/Greenberg anthology (orig. Planet Stories, Summer 1946)”—Posted by douglasSP, 12-31-2001, 09:16 AM

http://www.raybradbury.com/ubb/Forum1/HTML/000037.html

The "anthologized but not collected" stories number enough to make up a collection of their own.