This is a different series, predates the "teaching brats a lesson" series by a good deal. For some reason the author Anzu Kunko hasn't been writing continuations for a while. Been watching for new chapters but nothing so far.
As for the flower, in Japanese schools they place a flower on the desk of a recently-deceased student. Putting the flower on her desk is kind of like putting a eulogy on there, a sort of "wish you were dead" type of harassment. My take is she delt like moving the flower would just invite even more bullying, especially if everyone else in class just sort of accepted it.