Wheat’s Evil Twin Has Been Intoxicating Humans for Centuries (2016)(atlasobscura.com)
According to Wikipedia, it’s not the plant itself that’s toxic, but rather a fungus that can infect the plant, much as ergot infected other grains.
From what i can find, the difference is that ergot is parasitic and rare but the fungus growing on darnel is symbiotic and common.
Polish wikipedia says up to 86% of seeds carry it but without source. This paper  says 70% of 'wild populations' of related L. perenne, implies infection in darnel (L. temulentum) is also prevalent, but notes most populations have low frequency of infected individuals and then tries to explain that.
This seems similar enough to the allergy commonly associated with peanuts to be worth mentioning too.
Yes. I found this paper which talks about it more http://www.sidthomas.net/pdf/paperpdfs/Thomas%20et%20al%20Jo...
p34 talks about its constituent properties. Crucially no one is quite sure what the exact active component is
Okay, that makes the article make more sense. Most of the article the author claimed it was quite dangerous, but then they later cited a study which it was up to 10% of a harvest. I didn’t know how to make those make sense together.
German Wikipedia even notes that the fungus is related to ergot.
I expected this to be about ergot , a fungi with hallucinatory effects.
It's suspected that ergot caused the Strasbourg dancing plague of 1518 
It's also been suggested as a factor in the events that lead to the Salem witch trials:
Could someone post a version of this article that doesn’t cause iOS safari to crash?
You could read this source which the article seems to have referenced quite liberally.
Could someone find out why it crashes, is it exploitable? :D
Loads fine on my iPhone on iOS 13.7 and iPad on 14.1, perhaps the article has been fixed?
Hangs halfway through loading on Safari/Big Sur as well.
Thought this would be about alcohol