Most of the sea mushrooms in China are produced in Donggang and Zhuanghe in Liaoning Province. Because of the need of long-distance transportation and preservation, they will be coated with sodium sulfite, which is harmful to human health. It will also be soaked in formaldehyde, so please be careful when buying.
The price is not expensive either. Some restaurants have this cold sea mushroom, probably around 25 yuan. It can be bought in major hotels and aquatic products markets.
See/BBS/2005 _ 01/28/1106897356884.jpeg for the picture of sea mushrooms.