The vendors and guides on and around Hailuogou glacier sell a small plant. Its name is Cong1 Cao3. The vendors usually keep it in a little box and the guides keep it in a cigarette box. It can be as long as a cigarette, but usually shorter and less thick. It has a thin skin of dark brown covering a lighter interior.
Cong cao sells for about 5rmb dried and 20rmb fresh.

Please don't buy it.

It's sold under the pretext as being the best thing around for mountain sickness.
First of all...you're not really that high at Hailuogou. Second of all, if you're with a tour, chances are you won't be up there that long anyway.
And lastly, it's expensive and it won't work if you already have a headache.
This plant only grows above 4000 metres. It has no leaves, no fruit, no seeds. It propagates underground. It looks like a piece of thick brown grass.

On Gonggashan,it's becoming scarce.

Li Tang, the highest city in the world, lies in Ganzi Tibet Perfecture, Sichuan Province.