Liz, better check carefully what comes up!! a guy I met at a Botanical Society of the British Isles meeting was doing research into the appearance of strange and non-native plants on waste ground in London, the first likely suspected source for some of the species was bird seed , so he tried planting bird seed to see if it could happen, He had to destroy his seedlings when he showed them to the organisers and they were instantly identified as Cannabis Sativa!!!!