Rougui tea is a Wuyi Oolong tea. The name literally means "cassia". The tea can be difficult to prepare, but its distinctive sweet aroma can be brought out up to 7 steepings. It was first developed during the Qing Dynasty.
This tea may be traditionally processed producing a dark dry leaf and a rich smell or processed according to new consumer standards, giving it a leaf of mixed color and a more fruity aroma.
For a more comprehensive treatment, see the article on Wikipedia.