My understanding is that we don't even know for sure if it went extinct. We just don't know what it actually was/is. There's been a number of extant species tha

My understanding is that we don't even know for sure if it went extinct. We just don't know what it actually was/is. There's been a number of extant species that people have proposed as being silphium, but it's very hard to say if any of them actually are, and if so, which.