Toothed Clubmoss  (Huperzia serrata) is also known as Fir moss or Chinese Club Moss which contains the acetylcholinesterase inhibitor Huperzine A

The species is native to eastern Asia (China, Tibet, Japan, the Korean peninsula, the Russian Far East)

Huperzine A is used in Chinese Traditional Medicine (CTM) to improve memory and mental function in people with Alzheimers or dementia types but is also used for depression, schizophrenia, and many other conditions, but there is no good scientific evidence to support any of these uses.