I don’t get it, when it somehow appears that she don’t even know that there are silly flowers on her head
That was an obvious bad joke and troll by the writers lol. Uiharu should know the flowers are there. She removed her hairband when she was ill once and there was also one incident where she blatantly took off one flower from there.

Anyway, I suppose the second half of Railgun can be considered canon in a way, just not in the context of the manga maybe. After all, Kamachi Kazuma (Index/Railgun's author) was the one who wrote the stories' drafts for Episodes 13 - 24. ^^
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