I didn't see any reports on California Poppy on erowid and couldn't find much of anything on the net so I decided to try it and find out. After seeing a picture of it online, I went out side and realize this stuff grows everywhere in central California!! It's even a popular flower for planter boxes! Anxious to try it, I decided to start slow and eat a small part of one of the lilies. I didn't think such a small dosage would do anything but to my surprise within 20 minutes I was very relaxed. The buzz is mild and feels like a combination of an opiate and kava kava. When I go out and do my normal business I can tell more that it gives me low anxiety, calms nerves and generally makes me care free.
Overall this is a great buzz for feeling relaxed and care free but don't expect a 'high'. It produces stronger relaxation then lettuce opium and is on about the same level as kava kava. I could see this intensifing an opiate buzz (mixing it with hydrocondone, codeine ex....).
I haven't tried smoking it but I could definitely see it producing better effects from smoking rather than oral. If you want to relax go for it but don't get too excited about it.