Chamomile.
A classic evening tea. What to have if you want something soothing and don't want to caffeinate yourself.
It's one of the few teas I think is best on its own. Well steeped, but without sugar or milk or cookies or anything.
I don't think it's dandelions, but it is flowers, though the flavour is closer to dandelions than anything else I remember inhaling. ("Floral" used for tea, in my mind, means a sensation more abrasive and perfumed – a taste selected to seem apart from comestibles – but chamomile isn't that either.)