Related Clues:

• The weed
• (Treated leaves of) American plant
• Put that in your pipe and smoke it!
• Plant associated with serious health risks
• It's something to chew on that it's useless in the dark
• Boot out airman caught entering Virginia, say
• For a change, Cabot & Co goes up in smoke
• Snuff stuff
• Having turned back nearly half way across ocean, explorer leaves from the Americas
• Cash crop for the southern American colonies
• Caldwell's "__ Road"
• Transatlantic sailor turned up with firm's American export
• Leaves explorer upset over business
• Smoked narcotic plant
• Source of nicotine