no access to wildflower book, but they're some kind of thistle things that I -- and probably you -- have certainly seen before in the US.
I thought: If spot metering and +.33 is good for white flowers, maybe spot and .00 is good for yellow ones. And yes indeed!
Should've tried something similar with the one with the seeds blowing away, but I was busy wondering whether it would be able to capture them well with them whipping in the wind...