Poisonous Plants...?

I have to do a project on one poisonous plant that is native to and widespread in New England for my Field and Forage Crops cl.I've been looking online and I found a great resource in a big list on Cornell's website,except it doesn't say where the plant is found.The plant has to be poisonous to livestock and/or horses,doesn't matter if it is to people.Anyone have any suggestions,or know where I can find this information?I was thinking foxglove,or milkweed,but I don't know where they are from,so it doesn't really help me,haha.