A narcotic plant found in a hollowed bone is shedding new light on Roman civilization. Black henbane (Hyoscyamus niger) is a well known plant to biologists. It grows in Europe and Asia and is related to tobacco and the extremely toxic nightshade. Given its relatives, it’s not surprising then that black henbane can be used both as a narcotic and as a psychoactive substance. Archaeologists are also quite familiar with the substance as they’ve been finding it at all sorts of sites, including Roman sites. It’s a tantalizing find: on one hand, you really want to infer that the Romans were using thi…