Andrew,

Silphium became extinct in Roman times, due to over-harvesting, and
asafoetida was used as a substitute.

You can read more about this foul-smelling resin (it wasn't called
"divel's dreck" for nothing) at
http://www.hvinet.com/gallen/Asafoedita.html.

Gary



Andrew Dalby wrote:
> I suppose that by 'assa foetida' (which is the correct
> French spelling, incidentally) Flaubert means silphium?