Mandrake Roots Rock

Reading the new history of the 13th Floor Elevators I came across this passage documenting Roky's initial slide into madness:

Tommy (Hall) used Asthmador as part of Roky's draft avoidance regimen. This was an asthma relief preparation that contained the active ingredient Atropine, a psychoactive compound present in both mandrake root and belladonna.




A few sentences later:

Atropine is the same substance present in Mandrax (from the mandrake root) which was heavily abused by Pink Floyd's madcap leader Syd Barrett and has often been attributed to the final crack in his sanity.



Wikipedia provides this interesting mandrake root factoid:

It was a common belief in some countries that a mandrake would grow where the semen of a hanged man dripped on to the earth.

Lacking that option, I did some web searching and found that you can buy mandrake seeds and make your own witches brew.