I was introduced to these teas by some friends who run a tea business and had a booth at one of my recent pagan gatherings. I've found them at my local food co-op, at a specialty tea shop in SF, and on various tea sites on the Internet.
As I said, they are bunches of tea leaves tied so that as they brew in a glass pot or carafe, they appear to be unfolding flowers. I have one that I brew in a glass pitcher, it's called Jasmine Fairy Maidens. The green leaves unfold, orange blossom leaves expand and three white blossoms float upwards on a tiny string. All from a bunch of tea leaves tied to about the size of those jumbo gumballs.
I prefer green tea to black, so I've only tried green ones, but I understand they come in many varieties.