Origin: The origin of Leichhardt's Thornapple is Mexico (Symon & Haegi 1999). History: Leichhardt's Thornapple was a very early introduction to Australia. It was found by Ludwig Leichhardt in 1843 at Comet River in central Queensland (Purdie et al. 1982). Its mode of introduction is unknown. maybe you have seen this already...it comes from http://www.environment.gov.au/cgi-bin/biodiversity/invasive/weeds/weeddetails.pl?taxon_id=2996