Pu Erh

Pu'er or pu-erh traditionally produced in Yunnan Province, China, is a variety of fermented tea.

Fermentation refers to microbial fermentation, typically applied after the tea leaves have been sufficiently dried and rolled.
It is known as 'puer,' 'pu'er,' 'po lei' and 'bolay' tea, and 'dark tea' or 'black tea' in China, which is a semi-rare type of tea.
Pu-erh tea is made of Camellia Sinensis, from Yunnan large-leaf varietal. 
It is typically processed into compressed cakes, bricks and tuos.
Two kinds of Puer, Sheng Puer and Shu Puer, each style begins with Puer Mao Cha, basically coarse tea or half-processed tea.